Analcima
Analcima is a mineral with formula NaAlSi₂O₆·H₂O, in the Silicatos (Tectosilicatos) group. This specimen comes from Minas de Gilico, Calasparra, Murcia, Región de Murcia, España.
Description
Colourless cubic crystals with bevelled faces, arranged in a cavity on a greyish earthy matrix with green and reddish inclusions.
History of this specimen
With a weak, spot ultraviolet reaction due to inclusions of fluorapatite and calcite. The paragenesis is the typical one documented at the María mine, Gilico (Cehegín, Murcia), with the frequent association—as in this case—of fluorapatite, calcite and epidote.
About Analcima
Analcime is a tectosilicate zeolite with cubic structure, composed of sodium, aluminium, silicon and water. It typically crystallises in volcanic environments with moderate hydrothermal activity, and occurs as cubic or rhombododecahedral forms. It was first described in 1797 and is known for its reaction to ultraviolet light, especially in well-developed aggregates. Although usually an accessory mineral, in some deposits it forms conspicuous crystals valued by collectors.
About the locality
The Gilico Mines, at the Baños de Gilico between Calasparra and Cehegín, lie in an ophitic volcanic environment with cavities filled with zeolites and secondary minerals. They have been worked since Roman times. Although not industrially active, they yield analcime locally valued for its quality.
Technical data
- Catalogue No.
- 0022
- Composition
- NaAlSi₂O₆·H₂O
- Name
- Analcima
- Group
- Silicatos (Tectosilicatos)
- Category
- Cavella
- Associations
- fluorapatito calcita epidota
- Mine
- Minas de Gilico
- District / Municipality
- Calasparra
- Province
- Murcia
- Region
- Región de Murcia
- Country
- España
- Size (cm)
- 6 x 4 x 2.2
- Weight
- 85.2 g
- Etymology
- From the Greek "ἀναλκιμος" ("analkimos"), meaning "weak", in reference to its low electrostatic charge when rubbed.
- Quality
- Buena
- Value trend
- Estable
Related specimens
- Abellaíta — España
- Abernathyita — España
- Abernathyita — España
- Abernathyita — España
- Aerenita — España
- Aerinita (fibrosa) — España
- Afghanita — Afganistán
- Afghanita — Afganistán