Calcita Ahumada
Calcita is a mineral with formula CaCO₃, in the Carbonatos group. This specimen comes from Brushy Creek Mine, Reynolds County, Greeley, Missouri, Estados Unidos and joined the Terrium collection in 1994.
Description
Two principal scalenohedral crystals in smoky grey tones. The larger bears a very dense coating of marcasite microcrystals speckled with chalcopyrite. Resting on it is a smaller scalenohedral crystal, clean, well defined, and without metallic coating. On the back a third crystal appears, flatter and opaque, partially concealed by the matrix. The group has architectural presence and volume.
History of this specimen
This piece comes from material recovered during the contract mining campaign in Drift #106 at Brushy Creek in 1994, which yielded about twenty-four tonnes of calcites with marcasite and chalcopyrite.
About Calcita
Classic Brushy Creek material in which marcasite and chalcopyrite typically form thin metallic coatings on smoky calcite scalenohedra. In many specimens, as in this one, a two-stage development is evident: the original scalenohedra were first coated by chalcopyrite, and subsequently calcite regrew over them, leaving perfectly formed visible crystals. This growth pattern is one of the most characteristic features.
About the locality
Brushy Creek is a mine in the Viburnum Trend, known for its lead and zinc sulphides and for grey calcites with metallic coatings.
Technical data
- Catalogue No.
- 0256
- Composition
- CaCO₃
- Name
- Calcita
- Variety
- Ahumada
- Group
- Carbonatos
- Category
- Meritum Persé
- Associations
- marcasita calcopirita
- Mine
- Brushy Creek Mine
- District / Municipality
- Reynolds County
- Province
- Greeley
- Region
- Missouri
- Country
- Estados Unidos
- Size (cm)
- 6 x 4 x 3
- Weight
- 57.8 g
- Acquired
- 1994
- Ex-collection
- Sergio Petetrich
- Etymology
- From the Greek "chalix", lime.
- Quality
- Muy buena
- Value trend
- Estable
Related specimens
- Abellaíta — España
- Analcima — Estados Unidos
- Andersonita — España
- Aragonito (Pantojo) — España
- Aragonito (Azul (Toralina)) — España
- Aragonito — Italia
- Aragonito — España
- Aragonito (Pantojo) — España