Cuarzo
Cuarzo is a mineral with formula SiO₂, in the Silicatos [Tectosilicatos (Grupo Cuarzo)] group. This specimen comes from Minas da Panasqueira, Aldeia de S. Francisco, Covilhã, Castelo Branco, Portugal and joined the Terrium collection in 2025.
Description
Padme o El Sombrero Mejicano. Large prismatic quartz crystal, transparent to translucent, six-sided, partially coated by white dolomite rhombohedra and a lenticular, yellowish siderite on which cubic pyrite crystals with metallic iridescence grow. A sculptural, balanced composition with strong visual presence. It represents the mine's typical paragenesis very well.
About Cuarzo
Silicon dioxide; one of the most abundant minerals in the Earth's crust. At Panasqueira it commonly occurs as prismatic crystals, associated with sulphides and carbonates. Dolomite (CaMg(CO₃)₂) provides white contrast; siderite (FeCO₃) adds ochre and yellow tones; and pyrite (FeS₂) the characteristic golden, iridescent metallic lustre.
About the locality
The Panasqueira mine in Portugal is one of the world's most famous deposits for the quality and variety of its mineral associations. Active since the 19th century, it has produced iconic specimens of quartz, fluorapatite, siderite, wolframite and arsenopyrite, accompanied by dolomite and pyrite.
Technical data
- Catalogue No.
- 0164
- Composition
- SiO₂
- Name
- Cuarzo
- Group
- Silicatos [Tectosilicatos (Grupo Cuarzo)]
- Category
- Estélites
- Associations
- dolomita siderita pirita
- Mine
- Minas da Panasqueira
- District / Municipality
- Aldeia de S. Francisco
- Province
- Covilhã
- Region
- Castelo Branco
- Country
- Portugal
- Size (cm)
- 6 x 5 x 4.5
- Weight
- 79 g
- Acquired
- 2025
- Ex-collection
- Diego Navarro
- Etymology
- From the German "quarz", of uncertain origin, perhaps derived from an old Slavic root "tvrd" (hard).
- Quality
- Notable
- Value trend
- Al alza
Related specimens
- Autunita — Portugal
- Autunita — Portugal
- Autunita — Portugal
- Autunita (Verde) — Portugal
- Cristobalita — Estados Unidos
- Cuarzo — Madagascar
- Cuarzo (Ahumado) — Namibia
- Amatista — Kazajistán