Pentagonita
Pentagonita is a mineral with formula Ca(VO)Si₄O₁₀·4H₂O, in the Silicatos group. This specimen comes from Wagholi Quarry, Wagholi, Pune, Maharashtra, India and joined the Terrium collection in 2025.
Description
Radial, star-shaped aggregate with all points well defined, perfectly formed within a cavity lined by white drusy crystals.
About Pentagonita
Hydrated calcium-vanadium silicate, rare and much valued for its intense blue colour and radial habit. Polymorph of cavansite, but scarcer and harder to find with perfect crystals. Its formation requires very specific conditions in cavities of altered basalts, so each well-formed specimen is a rarity. It has only been found in significant quantity in India, specifically in the Wagholi quarries.
About the locality
The Wagholi Quarry, type locality of pentagonite, is the principal worldwide source of quality specimens. The species forms in cavities of altered basalts, associated with zeolites and other secondary silicates.
Technical data
- Catalogue No.
- 0103
- Composition
- Ca(VO)Si₄O₁₀·4H₂O
- Name
- Pentagonita
- Group
- Silicatos
- Category
- Cavella
- Matrix
- Basalto
- Associations
- heulandita-Ca stilbita-Ca
- Mine
- Wagholi Quarry
- District / Municipality
- Wagholi
- Province
- Pune
- Region
- Maharashtra
- Country
- India
- Size (cm)
- 4 x 4 x 4
- Weight
- 68.8 g
- Acquired
- 2025
- Etymology
- From the Greek 'penta' (five) and 'gonia' (angle), after the pentagonal shape of its twins.
- Quality
- Notable
- Value trend
- Estable
Related specimens
- Aerinita (fibrosa) — España
- Apofilita — India
- Asbesto —
- Atacamita — Chile
- Boltwoodita — Namibia
- Boltwoodita — Estados Unidos
- Calcita (Melada) — India
- Cavansita — India