Cuarzo
Cuarzo is a mineral with formula SiO₂, in the Silicatos group. This specimen comes from Mina Casapalca, Casapalca, Chicla, Huarochirí, Perú and joined the Terrium collection in 2000.
Description
Translucent white quartz crystals, prismatic with blunt terminations, forming a fan-like crest on a metallic base of bright golden pyritohedra, intergrown with dark grey crystals of the tetrahedrite subgroup.
About Cuarzo
Casapalca is a major Pb–Zn–Ag polymetallic district, akin to Madan, with quartz, pyrite, galena, sphalerite and sulphosalts. The distinction in this piece is not an exclusive paragenesis, but the visual prominence of Casapalca tetrahedrite: dark, tetrahedral crystals with intense metallic lustre and steel-grey colour, associated with quartz and pyrite in classic specimens circulated in the 1980s and early 1990s. In an industrial mine such pieces only survived if someone noticed them in time—miners who recognised a well-crystallised cavity and spared it before it reached the crusher. Their history as collection objects starts there too: not only in geology, but in the eye of those who protected them from indifference.
About the locality
An Andean Pb–Zn–Ag polymetallic district worked intensively since the 20th century, with a notable feat of engineering: the Graton Tunnel, built between 1960 and 1970, was a response to the "underground hell" that threatened to shut Casapalca due to massive flooding and temperatures up to 50°C. In fact they are two twin tunnels, 3×3 m, operating as a gravity drainage system and a giant lung, evacuating water from the workings and circulating fresh air to cool the depths, ensuring the viability of the mine.
Technical data
- Catalogue No.
- 0396
- Composition
- SiO₂
- Name
- Cuarzo
- Group
- Silicatos
- Category
- Cresta Montis
- Matrix
- Pirita
- Associations
- Pirita pseudomorfa de pirrotita; subgrupo de la tetrahedrita
- Mine
- Mina Casapalca
- District / Municipality
- Casapalca
- Province
- Chicla
- Region
- Huarochirí
- Country
- Perú
- Acquired
- 2000
- Ex-collection
- Juan Cabezas
- Etymology
- From the German «Quarz», an old word of uncertain, probably Slavic, origin.
- Quality
- Muy buena
- Value trend
- Estable
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