Cianita Negra
Cianita is a mineral with formula Ca₂(Mg,Fe)₅(Si₇Al)O₂₂(OH)₂, in the Silicatos (Inosilicatos) group. This specimen comes from Ribeirão da Folha, Minas Novas, Minas Gerais, Brasil and joined the Terrium collection in 2025.
Description
Black, highly lustrous spray. Prismatic bundle of elongated, parallel crystals with sharp terminations and a strong silvery metallic lustre. The aggregate forms a dense, sharp blade, opening in a fan towards the upper end. No coatings or impurities.
About Cianita
These pieces, long circulated as "witch's broom", were often sold in esoteric and commercial markets under the erroneous name "taramite". Genuine taramite is a different amphibole, rare and unrelated.
About the locality
To put it in perspective, Minas Gerais, in south-eastern Brazil, covers practically the same area as the whole Iberian Peninsula, about 586,000 km². That scale helps explain its extraordinary mineral diversity: not only because of the richness of its soils, but because that richness extends over an immense territory. And it is worth keeping the context: Brazil, at about 8.5 million km², is a country of continental dimension, comparable in scale to the United States and far above any European country. The problem is the mental image that the Mercator projection of the world map has put in our heads by shrinking countries near the Equator to an absurd degree.
Technical data
- Catalogue No.
- 0243
- Composition
- Ca₂(Mg,Fe)₅(Si₇Al)O₂₂(OH)₂
- Name
- Cianita
- Variety
- Negra
- Group
- Silicatos (Inosilicatos)
- Category
- Estélites
- Mine
- Ribeirão da Folha
- District / Municipality
- Minas Novas
- Province
- Minas Gerais
- Country
- Brasil
- Size (cm)
- 10 x 2.5 x 1.3
- Weight
- 53 g
- Acquired
- 2025
- Etymology
- From the toponym "Taram", an Italian locality where the species was described in 1904.
- Quality
- Muy buena
- Value trend
- Estable
Related specimens
- Aerenita — España
- Ágatha — Brasil
- Arfvedsonita — Marruecos
- Arfvedsonita —
- Cianita — Brasil
- Cianita (Negra (Taramita)) — Brasil
- Amatista — Brasil
- Cuarzo — Brasil