TERRIUM — A mineralogy cabinet


Calcedonia Estalactítica

Cuarzo is a mineral with formula SiO₂, in the Silicatos (Tectosilicatos) group. This specimen comes from Jalgaon Quarries, Jalgaon District, Nashik Division, Maharashtra, India and joined the Terrium collection in 2025.

Calcedonia Estalactítica from Jalgaon Quarries, Jalgaon District, Nashik Division, Maharashtra, India — Terrium

Description

Upward-growing stalactitic column with a frost-like aspect. Transparent ash-grey colour; tabular fluorapophyllite protrudes on the surface. Architectural silhouette, as if it were a mineral mould.

History of this specimen

I bought three specimens from the same lot: this large one arrived broken and I repaired it; a small one I dropped in a moment of nerves; the third, slightly smaller, was the only one that remained intact.

About Cuarzo

Chalcedony is a microcrystalline variety of quartz, formed by fibrous aggregates of silica. In Jalgaon it commonly lines basaltic cavities, often associated with fluorapophyllite, heulandite and other zeolites. Its compact texture and drusy coating produce that characteristic "frost" aspect.

About the locality

Typical textures of the amygdaloidal cavities of the Deccan basalts at Jalgaon, Maharashtra, renowned for chalcedony, apophyllites and zeolites.

Technical data

Catalogue No.
0072
Composition
SiO₂
Name
Cuarzo
Variety
Calcedonia Estalactítica
Group
Silicatos (Tectosilicatos)
Category
Estélites
Associations
flúorapofilita
Mine
Jalgaon Quarries
District / Municipality
Jalgaon District
Province
Nashik Division
Region
Maharashtra
Country
India
Size (cm)
16 x 6 x 3.3
Weight
80 g
Acquired
2025
Etymology
From the classical toponym "Chalcedon" (Χαλκηδών), a city of Bithynia.
Quality
Buena
Value trend
Estable

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