Mineral Localities and Mining Districts in BOLIVIA

Cerro Rico, Cerro de Potosí, Tomás Frías, Potosí

The Cerro Rico in Potosi - Image Credit: Adam Jones, CC BY-SA 2.0

Cerro Rico, meaning ‘Rich Hill’ in Spanish rises above the city of Potosí in southern Bolivia and is one of the most historically significant mining sites in the world. Discovered by Spanish colonists in 1545, its enormous silver deposits transformed Potosí into one of the richest cities of the colonial era and supplied vast quantities of silver to Spain for more than three centuries. Geologically, Cerro Rico is a volcanic dome composed mainly of dacite and associated breccias. The mineralisation occurs in numerous hydrothermal veins rich in sulphide minerals. The ore system includes complex assemblages of silver, tin, and base-metal minerals deposited during several mineralising stages fed by upwelling magma. Although the mine is best known for its silver production, it has also yielded notable mineral specimens for collectors. These include well-crystallised stannite, tetrahedrite, enargite, bournonite, and pyrite, often associated with quartz or siderite. Attractive specimens of cassiterite from the tin-rich stages of mineralisation are also known. Overall, Cerro Ric is known for at least 75 different mineral species, including two type location minerals, ottemannite and berndtite, both rare tin sulfides. Despite centuries of intense exploitation, Cerro Rico continues to be worked today by cooperative miners. For mineral collectors, it remains one of the classic historic mining districts of South America.

Llallagua – Catavi Mining District, Rafael Bustillo, Potosí

Vauxite - Image Credit: Robert M. Lavinsky, CC BY-SA 3.0

The Llallagua mining district lies in northern Potosí Department near the town of Llallagua and is historically centred on the famous Siglo Veinte and Catavi mines. During the twentieth century this district became one of the world’s most important sources of tin and played a major role in the development of Bolivia’s economy. The ore deposits occur within a Tertiary volcanic complex composed mainly of rhyolitic and dacitic intrusions. The mineralisation developed when hydrothermal fluids circulated through fractures in these rocks, forming an extensive system of tin-bearing veins. At the peak of production in the 1920s, as many as fifteen major veins were being worked simultaneously. Mining at Llallagua reached its greatest importance in the early twentieth century under the control of powerful Bolivian tin barons, most notably Simón Patiño, whose operations helped establish Bolivia as a leading global tin producer. Although large-scale mining has declined, the district remains historically important and still yields occasional mineral specimens. The principal ore mineral is cassiterite, which occurs in veins and breccia zones together with a variety of sulfide minerals. For collectors, Llallagua is renowned for its excellent cassiterite crystals, typically dark brown to black, sharply formed, and sometimes several centimetres in size. These crystals are often associated with quartz, arsenopyrite, pyrite, sphalerite, and stannite, forming attractive specimen groups which are highly sought after. Llallagua is also the type locality for six mineral species: ferrivauxite, jeanbandyite, metavauxite, paravauxite, sigloite, and vauxite. The vauxite-group minerals and sigloite are all iron–aluminium phosphates, distinguished by variations in the proportions of their principal constituent elements.

Cerro Chorolque, Atocha, Sud Chichas, Potosí

Native Bismuth - Image Credit: Robert M. Lavinsky, CC BY-SA 3.0

The Chorolque mining district is located in southern Bolivia near the town of Atocha in Potosí Department. The mines are situated high on Cerro Chorolque, a prominent mountain rising above 5,500 metres, making it one of the highest mining operations in the world. Geologically, the deposit is associated with a volcanic dome complex composed mainly of dacitic rocks. The mineralisation formed through hydrothermal processes that created a network of veins rich in tin and associated metals. Cassiterite is the principal ore mineral, accompanied by complex sulfide assemblages. Chorolque is another Bolivian location renowned among mineral collectors for its distinctive cassiterite crystals, often sharply formed and sometimes twinned. These may occur alongside stannite, pyrite, sphalerite, and quartz. Attractive specimens featuring cassiterite crystals on quartz matrix have long been prized by collectors. Mining at Chorolque began in the nineteenth century but expanded significantly during the twentieth century when Bolivia became one of the world’s leading tin producers. Although production has declined, the district remains historically important and continues to yield occasional mineral specimens.

Tasna Rosario (Tazna) mine, Cerro Tazna, Cotagaita, Nor Chichas, Potosí

Ferberite - Image Credit: Robert M. Lavinsky, CC BY-SA 3.0

The Tasna mining district lies in southern Potosí Department and is best known among mineral collectors for producing some of the finest ferberite crystals in the world. Mining in the region began during the Spanish colonial period but expanded significantly during the nineteenth and early twentieth centuries. Geologically, Tasna is part of the Bolivian tin-silver belt associated with Tertiary volcanic activity. The mineralisation occurs in hydrothermal veins cutting mainly hornfels host rocks and consists primarily of tungsten and bismuth ores and a complex assemblage of related sulfide and sulfosalt minerals formed during multiple stages of mineral deposition. Tasna is particularly celebrated for its outstanding ferberite crystals, which commonly form sharp twins with brilliant metallic lustre. These specimens are often found in association with quartz, pyrite, tetrahedrite, and sphalerite. Because of their distinctive crystal habit, large size and aesthetic appeal, Tasna ferberite specimens are highly prized by collectors and appear in many major mineral collections worldwide. Other collectible minerals from Tasna include those of bismuth, such as, bismuthinite, bismutite, joséite, ikunolite, preisingerite, rooseveltite, zaïrite and native bismuth itself. The minerals containing tungsten include the already mentioned ferberite and the bismuth tungstate, russellite. Although large-scale mining had declined, local artisanal mining continues to produce specimens, ensuring that the locality remains one of Bolivia’s famous sources of classic mineral specimens.  

Pulacayo Mine, Huanchaca, Uyuni, Antonio Quijarro, Potosí

Pulacayo Mining Village - Image Credit: Manuel Menal, CC BY-SA 2.0

The Pulacayo Mine, located approximately 20 km northeast of Uyuni in Potosí Department, is one of Bolivia’s largest and most historically important silver mines. Sometimes referred to as the Huanchaca Mine, after the nearby settlement where ore was processed, it developed following its discovery in 1833 and became a major centre of silver production during the nineteenth-century mining boom. For a while it was owned by the former president of Bolivia, Aniceto Arce, whose house still stands among the mine’s preserved buildings. The riches coming from the mine transformed Bolivia, raising the population’s living standards, funding the development of political infrastructure, bringing about the country’s industrial revolution and creating Bolivia’s extensive network of railroads. Geologically, Pulacayo is associated with volcanic activity on the Bolivian Altiplano, with the mineralisation hosted within a large block of dacite - a fine-grained to porphyritic, high-silica volcanic rock formed from rapid cooling lava, featuring predominantly plagioclase feldspar and quartz. The main veins, including the Veta San Tomas, Veta Corpus, Veta Pacamayo, Veta Tajo and Veta Animas are all hydrothermal systems within zones of intense metamorphism, carrying considerable amounts of silver and some lead and zinc. Mining at Pulacayo reached considerable depths, with workings extending to around 1,100 metres below the surface. Operations became increasingly difficult, however, due to the presence of hot underground springs at temperatures of up to 60 °C, along with large volumes of carbon dioxide gas. By the 1990s, most underground mining had ceased, with only limited gypsum production and reworking of historic mine dumps continuing. For mineral collectors, Pulacayo is best known for its silver sulfosalt specimens, particularly pyrargyrite, stephanite, miargyrite and freibergite-group, many of which form striking large metallic crystals. Additional minerals include galena, tetrahedrite, tennantite, bismuthinite, bournonite, sphalerite, and quartz. Today, Pulacayo remains a classic Bolivian locality, valued both for its mineralogical diversity and its rich mining heritage.

Colquechaca Mining District, Colquechaca, Chayanta, Potosí

Argyrodite - Image Credit: Rock Currier, CC BY 3.0

The Colquechaca mining district lies in northern Potosí Department and has been an important centre of silver mining since Spanish colonial times. The name ‘Colquechaca’ derives from the Quechua language and roughly translates to ‘silver bridge’, reflecting the district’s long association with precious metal extraction. Discovered earlier by the indigenous people but developed during the Spanish colonial period, it became one of the notable historic silver-producing regions of Bolivia and remains active on a smaller scale today. Geologically, the deposits occur within a volcanic region composed mainly of Tertiary volcanic rocks. The mineralisation formed through hydrothermal processes that created polymetallic veins rich in silver, lead, and zinc. These veins host a complex assemblage of sulfide and sulfosalt minerals typical of many Bolivian silver districts. They include the classic silver sulfosalt specimens of pyrargyrite and argyrodite, which are some of the best worldwide specimens of these minerals. Other notable silver sulfosalts include stephanite, miargyrite, hocartite, owyheeite and polybasite. Colquechaca is also the type locality for the silver-tin sulfide, cranfieldite, and is also well known to collectors for specimens of galena, tetrahedrite, sphalerite, and quartz, often displaying attractive crystal forms. The locality is closely linked with the nearby settlement of Aullagas, which appears on many older specimen labels. However, Aullagas is not a separate mineral locality but rather an earlier mining settlement located a short distance from the present town of Colquechaca. Both towns exploited the same ore veins, such as the Gallofa–Embudo vein, which historically was worked from Aullagas but is now accessed from Colquechaca via adits like Progreso and San Bartolomé. Although mining activity has declined from its historic peak in the eighteenth and nineteenth centuries, Colquechaca remains an important and classic locality within Bolivia’s tin–silver belt, valued for both its mineral specimens and its rich mining history.

Colavi Mining District, Tacobamba, Cornelio Saavedra, Potosí

Vivianite - Image Credit: Robert M. Lavinsky, CC BY-SA 3.0

The Colavi mining district and the Colavi Mine are located in Potosí Department, 40 kilometres northeast of the city Potosí in the Bolivian Altiplano. The district has been known for its tin mineralisation since the early twentieth century and forms part of Bolivia’s extensive tin-producing belt. Geologically, the deposits occur within volcanic and intrusive rocks related to Tertiary magmatic activity in the Andes. Hydrothermal fluids associated with these intrusions produced vein systems containing cassiterite and associated sulfide minerals. Although the district is primarily known for its tin ores, Colavi has produced interesting mineral specimens for collectors. Apart from cassiterite crystals these include baryte, bismuthinite, cosalite, dickite, gibbsite, hocartite, kësterite, native bismuth, tetrahedrite, pyrite, valentinite and vivianite. It is also especially well known for its striking crystals of pale-green ludlamite, as well as being the type location for the bismuth oxide, bismite. Mining in the district developed during the period when Bolivia’s tin industry was dominated by powerful mining companies in the early twentieth century. While large-scale operations have diminished, Colavi remains an important representative locality within the Bolivian tin province.

San José Mine, Oruro, Cercado, Oruro

Stannite - Image Credit: Robert M. Lavinsky, CC BY-SA 3.0

The San José Mine lies beneath the city of Oruro in western Bolivia and is one of the country’s most notable mineral localities. Mining in the district dates to the late sixteenth century when Spanish explorers began exploiting the rich silver and tin deposits discovered in the region. Geologically, the deposit occurs within a volcanic complex composed primarily of dacitic rocks. The mineralisation formed through hydrothermal activity that produced a dense network of polymetallic veins rich in silver, tin, antimony and other minor base metals. The veins contain a diverse suite of sulfides and sulfosalts typical of high-level epithermal systems. For collectors, San José is particularly famous for superb andorite and bournonite crystals, often showing well-formed shapes and high metallic lustre. The mine has also produced excellent specimens of stannite, tetrahedrite, pyrargyrite, and arsenopyrite, commonly associated with quartz or pyrite. Other minerals containing silver include acanthite, diaphorite, fizélyite, freibergite, hocartite, miargyrite, owyheeite, petrukite, quatrandorite, ramdohrite, stephanite and terrywallaceite. San José is also the type location for the highly complex silver-copper-lead sulfosalt, cuprosenandorite, and for the zinc-iron sulfide, wurtzite. Historically there has been some confusion about the labelling of stannite and ferrokësterite mined from here, with some misattribution between the two minerals. Also, jamesonite is often mislabelled as zinkenite, although the atter also occurs in it own right. Finally, many specimens attributed to San Jose mine are actually from the nearby Itos mine. Today, mining continues intermittently in the district, although the most recent production has refocussed more on ore extraction than specimen recovery. Nevertheless, San José remains one of the classic mineral localities of Bolivia and a renowned source of fine sulfosalt specimens.

Itos Mine, Oruro, Cercado, Oruro

Andorite-Zinkenite - Image Credit: Robert M. Lavinsky, CC BY-SA 3.0

The Itos Mine lies within the mining district of Oruro, in Cercado Province, and forms part of the cluster of historic tin–silver mines developed around the city, alongside the better-known San José workings. It has long been worked as a tin–silver deposit, and modern mineralogical references note that specimens from Itos are often confused with those from neighbouring San José because both operations were closely linked administratively. Geologically, the mine is hosted in the same highly altered volcanic intrusive system that underlies several of Oruro’s other mines. The silver-tin mineralisation is associated with hydrothermal veining within altered volcanic rocks, part of the broader Bolivian tin–silver belt that gave Oruro its importance as a major mining centre. For mineral collectors, Itos is especially notable as a source of some of the world’s finest franckeite specimens. The mine is also recorded for minerals such as cylindrite, bournonite, cassiterite, stannite, jamesonite, chalcopyrite, wurtzite, stibnite and zinkenite, reflecting the complex sulfide and sulfosalt assemblages typical of Oruro. Because of this rich mineralogy, Itos remains an important classic Bolivian locality, valued both for specimen rarity and for its close association with one of the Andes’ great historic mining districts.

Huanuni mine, Huanuni, Pantaleón Dalence, Oruro

Ludlamite - Image Credit: Robert M. Lavinsky, CC BY-SA 3.0

The Huanuni Mine is located east of Oruro in the Bolivian Altiplano and is one of the country’s most important historic and economically important tin mines. The district developed rapidly in the early twentieth century when Bolivia emerged as one of the world’s leading producers of tin. It is widely regarded as the world’s richest cassiterite deposit. The ore is hosted within a volcanic complex composed largely of rhyolitic and dacitic rocks. Hydrothermal activity produced extensive vein systems rich in tin mineralisation. Cassiterite is the principal ore mineral, accompanied by sulfides such as pyrite, arsenopyrite, and sphalerite. Although primarily an industrial tin mine, Huanuni has produced attractive mineral specimens for collectors. Well-formed cassiterite crystals, often dark brown to black and highly lustrous, are the most notable. These may occur in association with quartz, arsenopyrite, and pyrite, forming striking specimen groups. Haununi is also the source of world class vivianite and ludlamite specimens, often as flattened tabular, transparent, bottle-green crystals and also for structurally complex minerals like franckeite, hisingerite and jarosite. The oxidation zone contains a number of secondary lead species, including linarite, plumbogummite, anglesite and pyromorphite, as well as the tin sulfides cylindrite, herzenbergite, rhodostannite, stannite and tealite. The mine is also the type location for aheylite and nikischerite. Mining operations at Huanuni continue today under state control and remain an important part of Bolivia’s mining industry and economy. For mineral collectors, specimens from the district represent classic examples from the Bolivian great tin-producing belt of the Andes.

Berenguela mining district, José Manuel Pando, La Paz

Rhodochrosite - Image Credit: The Assay House, Public Domain

The Berenguela mining district lies in La Paz Department near the border with Peru and is another of Bolivia’s historically significant polymetallic mining regions. Mining activity in the area dates back to the Spanish colonial period, when silver-rich ores were first exploited here. However, when the silver output began to decline, discoveries of copper and to a lesser extent zinc and manganese allowed mining to continue. At least six mines operated in the area, each with its own mix of metallic elements, their ores and associated minerals. The Choquepiña Mine became predominantly a copper mine, which occurs as the sulfides chalcopyrite, chalcocite, covellite and digenite, together with malachite as the main product of oxidation. The San José de Berenguela Mine produced managanese which occurs as a complex mix of manganese oxides and rhodochrosite, as well as zinc as the ore sphalerite The mine is also known for the rare silver sulfosalt, freieslebenite. The Pacocagua Mine worked a 350-meter-long vein on the south slope of Cerro Pacocahua for zinc and lead. The mine is also notable for the silver sulfide, acanthite, and for a number of rare silver sulfosalts that include pearceite and polybasite. Mining here was always difficult because hot mineralising fluids continue to circulate through the rocks causing flooding and raising the working temperatures for the miners. The remaining there mines, Manco Capac, Marimarini (Lourdes Ines) and San Luis Mine (Mary-Mary), were all zinc mines with some silver and occasional copper but are particularly notable for the presence of cadmium. This metal is usually present as the cadmium sulfide, greenockite, which occurs as yellow or red hexagonal crystals. Some of these zinc-cadmium veins extend for up to 1 kilometre underground. Geologically, the district consists mainly of volcanic and sedimentary rocks affected by hydrothermal mineralisation. Vein systems developed within these rocks and contain a complex suite of sulfide and sulfosalt minerals so typical of Andean polymetallic deposits. Although modern mining activity is limited compared with Bolivia’s major tin districts, Berenguela remains a noteworthy locality because of its complex mineralogy, rare minerals, cadmium mineralisation and its place in the long history of Andean mining.

Viloco Mine (Araca Mine), Loayza , La Paz

Cassiterite - Image Credit: The Assay House, Public Domain

The Viloco mine, also known interchangeably as the Araca Mine, lies about 80 kilometres southeast of La Paz in the Eastern Cordillera. The deposits are hosted in strongly altered sedimentary and intrusive rocks affected by Andean tectonics. Hydrothermal fluids associated with granitic intrusions formed tin-bearing veins rich in cassiterite. Mining developed in the early twentieth century as part of Bolivia’s rise as a major tin producer. Viloco is especially renowned for its exceptional cassiterite crystals, including distinctive almost spherical twins, making it one of Bolivia’s most important collector localities. In addition, this tin mine is the only source in Bolivia that occasionally produces transparent, highly gemmy, cassiterite of a quality suitable for faceting into semi-precious jewellery. Despite declining large-scale production, the district remains significant for both its geology and its classic mineral specimens.

Morococala Mine, Santa Fé mining district, Pantaleón Dalence, Oruro

Vivianite - Image Credit: The Assay House, Public Domain

The Morococala Mine in the Santa Fé mining district, lies northwest of Oruro in the central Bolivian Altiplano. The mineralisation is associated with Tertiary volcanic rocks and hydrothermal vein systems rich in tin and silver. Mining activity expanded during the late nineteenth and early twentieth centuries, contributing to Bolivia’s tin industry. The district is famous among collectors for outstanding vivianite crystals, often forming large specimens, of intense green and sometimes blue colour, occasionally together as part of the same crystal cluster. In addition, the mine has produced a number of rare silver species, including andorite, freibergite-group, gustavite, lillianite, matildite, ourayite and petrukite. The tin minerals include its main cassiterite and stannatite, as well as a number of accessory species that include berndtite, cylindrite, kësterite, petrukite, sakuraiite, stannoidite and teallite. Morococala remains one of Bolivia’s most distinctive mineral localities due to its unusual mineral associations and visually striking specimens.

Colquiri Mine, Colquiri, Inquisivi, La Paz

Creedite - Image Credit: The Assay House, Public Domain

The Colquiri district and mine are located 150 kilometres southeast of La Paz in southern La Paz Department, close to the border with Oruro, and lies at an altitude of around 4,200 metres within Bolivia’s prolific tin belt. It remains an important active zinc–tin mining district and gained particular fame in the 1970s for producing some of the world’s finest creedite crystals. Geologically, the Colquiri deposit consists of fissure-filling polymetallic veins formed during Oligocene–Miocene magmatic activity associated with the formation of the Andes. The mineralisation is hosted within folded Silurian sedimentary rocks, including shales and quartzites, which have been highly deformed. The ore occurs in hydrothermal veins filling faults with predominantly N–S and NNE orientations. Some of the individual veins reach up to 700 metres in length and 2 metres in thickness and the most important include Blanca, Rosario, San Antonio, and San Carlos. Mining intensified during the twentieth century under both private and later state control and continues today. The district is well known for a complex mineral assemblage including cassiterite, stannite, bismuthinite, siderite, sphalerite, cylindrite, franckeite, and other associated sulfides and sulfosalts. The Colquiri mine is the type location for the calcium-lithium-aluminium-fluoride, colquiriite, named after the location. Specimens from this mine and region are valued by collectors for their intricate paragenesis and their connection to Bolivia’s classic tin mineralisation.

Monserrat-Antequera mining district, Poopó Province, Oruro

Cassiterite var. Needle Tin - Image Credit: The Assay House, Public Domain

The Monserrat–Antequera district lies south of Oruro and includes several historic mines. Many have held several names and some of these were used interchangeably with the names of ore-bearing veins, thereby causing much confusion. Overall, the two main mines were the Monserrat mine, also called the Ichocollo mine, and the Antequera mine, which worked three sites called Bolivar, Tihua and El Salvador. The last of these worked the Santa Rosa vein, which is often also called the Santa Rosa mine. There were also a handful of smaller operations including Avicaya (Totoral) and Venus mines. Despite the naming complexity, all share near identical geology, consisting of volcanic rocks cut by hydrothermal veins formed during Andean magmatism. Mining in the area dates back to Spanish colonial times but expanded significantly in the nineteenth and twentieth centuries. The district is notable for complex sulfide and sulfosalt mineralisation, including the type locality for the lead-tin sulfide, teallite, first discovered in the Santa Rosa vein of the El Salvador mine. However, the Carguaycollo mine in neighbouring Potosí is also another contender for the first discovery. It’s worth noting that many specimens in collections labelled ‘teallite’, especially those from the San Jose mine in Oruro, are really franckeite. Mineralogically, the most diverse site was the Montserrat (Ichocollo) mine, producing specimens of bournonite, chalcopyrite, franckeite, jamesonite, marcasite, pyrrhotite, siderite, sphalerite, stannite, varlamoffite, vivianite and wurtzite, as well as the main ore cassiterite and the already mentioned teallite. For collectors, Antequera is an important reference source of rare and unusual mineral species within Bolivia’s wider polymetallic vein systems.

Chocaya-Animas mining district, Atocha, Sud Chichas, Potosí

Animas Mine - Image Credit: Mach marco, Public Domain

The Chocaya–Ánimas district, located south of Potosí, forms part of Bolivia’s southern tin–silver belt and represents a classic example of Andean polymetallic vein mineralisation resulting from tectonic events associated with the formation of these mountains. The district includes several closely related operations, notably the Ánimas, Siete Suyos, Oploca, and Chocaya mines, all of which exploit the same system of hydrothermal veins. In many cases, more than one mine has worked the same vein, and historically the operations were administered from a single office. As a result, it is often impossible to determine the exact source of individual specimens, and locality labels - both in collections and in the literature - can be inconsistent. For this reason, the entire group is commonly referred to collectively as the ‘Chocaya–Ánimas’ district, effectively representing different access points to a single mineralised system. Geologically, the deposits are hosted within volcanic rocks and formed through hydrothermal processes that created extensive vein networks rich in sulfides and sulfosalts. Metal mining began during the Spanish colonial period and continued into the modern era, contributing significantly to regional silver and tin production. For mineral collectors, the district is well known for its diverse and often complex mineral assemblages, including wurtzite, stannite, sphalerite and chalcopyrite, frequently occurring in intricate associations. In addition, the area is the type locality for six minerals, namely, aramayoite, clino-oscarkempffite, franckeite, oscarkempffite, ramdohrite and hocartite, nearly all rare antimony-silver-bearing species. The combination of geology, historical importance, mineral diversity and rare and unusual sulfide minerals make the Chocaya–Ánimas district one of Bolivia’s most notable and rewarding collecting localities.

Milluni Mine, Los Andes, La Paz

Milluni Lake - Image Credit: Warmiwaritas468, CC BY-SA 4.0

The Milluni mine is situated about 20 kilometres north of La Paz in the high Andes and is another example of a Bolivian deposit worked for silver, tin, and zinc. The mineralisation is again linked to igneous activity, with hydrothermal veins cutting through older metamorphic and sedimentary rocks intruded during the tectonic and volcanic processes that built the Andes. Mining at Milluni developed during the twentieth century and contributed to Bolivia’s wider tin industry. Although it is smaller and less well known than some of the country’s other mining districts, it has produced a range of minerals of interest to collectors, including cassiterite, boulangerite, stannite, tetrahedrite-group minerals, and chalcopyrite. Set within a harsh, high-altitude Andean landscape, Milluni reflects the determination of Bolivian prospectors and miners to exploit mineral resources even in remote and challenging environments.

Kami Mine, Ayopaya, Cochabamba

Japan Law Quartz - Image Credit: The Assay House, Public Domain

The Kami district is located in central Bolivia within the eastern Andes about 60 kilometres east of Cochabamba and is a rare tungsten–tin deposit. The mineralisation occurs in high-temperature hydrothermal veins within metamorphic rocks altered by intrusions into tourmaline-rich hornfels. Mining developed during the twentieth century as worldwide demand for tungsten increased, working a system of veins that ascend from an elevation of 2,900 m to 4,350 m on the slopes of Kami Mountain. The locality is best known for minerals such as ferberite, bismuthinite, scorodite, siderite, pitticite and magnetite and for minor gold, bismuth and arsenic which occur in their native form. However, Kami is particularly prized by collectors for its relatively abundant Japan-law twinned quartz crystals, often transparent, and occurring in well-defined vein cavities. The district represents a different style of mineralisation compared to Bolivia’s classic tin–silver belt, adding to its geological interest.

Huari-Huari Mine, Tomás Frías, Potosí

Mina Esperanza (Huari-Huari) - Image Credit: Ventura, CC BY 3.0

Huari-Huari lies in southern Bolivia about 30 kilometres northeast of Potosi and is a historic silver mining district within the Andean volcanic belt. The deposits occur in hydrothermal veins cutting volcanic rocks, similar to other Bolivian silver districts. Mining dates to Spanish colonial times and continued intermittently into the modern period. The district is known for its tin sulfosalt minerals such as jamesonite and tetrahedrite-group, as well as sulfides like sphalerite and stannite, typical of Bolivia’s Andean hydrothermal systems. In addition, the location is known for small amounts of the lead ore, galena, and very striking lead oxidation minerals pyromorphite and wulfenite. Overall, Huari-Huari remains a lesser-known but mineralogically interesting locality representing Bolivia’s long tradition of polymetallic mining.

Carguaicollo Mine, Uyuni, Antonio Quijarro, Potosí

Tealite - Image Credit: Robert M. Lavinsky, CC BY-SA 3.0

The Carguaicollo (Carguaycollo) Mine is located in the Bolivian Altiplano near Uyuni and is one of the more unusual deposits within the country’s tin–silver belt. It is notable as perhaps the only active tin mine in the world where one of the principal ores is a tin sulphide, rather than the more typical oxide cassiterite. Geologically, the deposit is hosted in volcanic rocks and consists of hydrothermal veins rich in sulfides and sulfosalts, formed during Andean magmatic activity. The mineralisation is particularly distinctive for its abundance of stannite, alongside minerals such as bournonite, stibnite, stibiconite, franckeite, tetrahedrite, and chalcopyrite, reflecting a highly complex sulfide-rich system. Mining began in the nineteenth century initially targeting silver. After a period of abandonment, the mine was rediscovered in 1926 by geologist Federico Ahlfeld and reactivated in the early twentieth century. It has operated since under various forms of ownership including a local mining cooperative. Today, the mine remains significant for its rare tin sulfide mineralisation and well-crystallised stannite and other specimens.