Allanita
Allanita is a mineral with formula (Ca,Ce,La,Y)₂(Al,Fe³⁺)₃(SiO₄)₃(OH), in the Supergrupo de la Epidota group. This specimen comes from Trimouns Talc Mine, Luzenac, Occitanie, Francia and joined the Terrium collection in 1998.
Description
Typical of this locality. The specimen is dominated by a long, dark, well-formed allanite crystal, clearly projecting over a base carpeted with white crystals. The main prism, typical of the monoclinic system, is elongated and slightly flattened, with smooth faces and well-defined edges. The cavity is open and shows the complete structure without obstruction, with a strong contrast between the dark crystal and the light matrix.
About Allanita
A classic of this French locality. Seldom found in well-defined crystals. It is a rare-earth element-bearing silicate, occurring as very elongate prismatic crystals, translucent and brown to toasted-honey in colour.
About the locality
In Luzenac (Ariège) allanite has been documented in pegmatitic and metamorphic veins. A classic locality for aesthetic crystals.
Technical data
- Catalogue No.
- 0071
- Composition
- (Ca,Ce,La,Y)₂(Al,Fe³⁺)₃(SiO₄)₃(OH)
- Name
- Allanita
- Group
- Supergrupo de la Epidota
- Category
- Cavella
- Matrix
- Calcita
- Associations
- dolomita
- Mine
- Trimouns Talc Mine
- District / Municipality
- Luzenac
- Province
- Occitanie
- Country
- Francia
- Size (cm)
- 8 x 6 x 5
- Weight
- 248.5 g
- Acquired
- 1998
- Ex-collection
- Aleydis Soliveres
- Etymology
- Named in honour of Thomas Allan (1777–1833), a Scottish mineralogist who first described it.
- Quality
- Muy buena
- Value trend
- Estable
Related specimens
- Allanita ((Ce)) — Pakistán
- Autunita — Francia
- Calcopirita (Irisada) — Francia
- Parsonsita — Francia