Marcasita
Marcasita is a mineral with formula FeS₂, in the Sulfuros group. This specimen comes from Mansehra Mine, Mansehra District, Khyber Pakhtunkhwa, Pakistán.
Description
Venus de Milorf. Botryoidal aggregate formed by four superposed metallic spheres, with very fine microgranular texture and dull metallic lustre. Rough, uniform surface over the whole piece.
About Marcasita
Iron disulphide, a dimorph of pyrite. Its botryoidal habit is uncommon and usually indicates rapid precipitation. In a collection it is a species to be treated with respect, because some pieces can become "sick". They alter, whiten, crack, crumble, and end up releasing powder and anomalous odours. In that process they generate iron sulphates and sulphuric acid, so they can damage nearby pieces, labels and storage materials. Although it is known that some microorganisms can accelerate the oxidation of iron and sulphur in certain contexts, in practice the decisive factor is to keep the piece in a dry, stable environment.
About the locality
There is no well-documented marcasite mine nor clear references to a specific working in Mansehra. This locality is often used as a catch-all label for pieces like this.
Technical data
- Catalogue No.
- 0260
- Composition
- FeS₂
- Name
- Marcasita
- Group
- Sulfuros
- Category
- Estélites
- Mine
- Mansehra Mine
- Province
- Mansehra District
- Region
- Khyber Pakhtunkhwa
- Country
- Pakistán
- Size (cm)
- 4.5 x 1.9 x 1.6
- Weight
- 42.3 g
- Etymology
- From the Arabic "marqashītā", an old name applied to various metallic sulphides.
- Quality
- Buena
- Value trend
- Estable
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- Brookita — Pakistán
- Calcita (Manganocalcita) — Pakistán
- Calcopirita (Irisada) — Francia
- Cinabrio — Eslovenia