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

Thin stalactitic formation with a grey-black inner channel, coated by minute quartz crystals that give a uniform lustre. The original growth channel is discernible along the central axis. With fins of apophyllite or some type of zeolite.

History of this specimen

I bought three specimens from the same lot: one large, about twenty centimetres, which arrived broken and beyond repair; another small one that I dropped on the floor in a moment of nerves; and this piece, the only one that remained intact. The remaining fragments will go to the secondary collection.

About Cuarzo

A microcrystalline variety of quartz, with vitreous to waxy lustre, commonly forming botryoidal or stalactitic structures produced by the precipitation of colloidal silica in volcanic cavities.

About the locality

Jalgaon, in the state of Maharashtra, is noted for stalactitic chalcedony formations and zeolite geodes; a classic Indian district for the abundance and diversity of its minerals.

Technical data

Catalogue No.
0254
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)
8 x 2.5 x 2
Weight
20 g
Acquired
2025
Etymology
From Latin "chalcedonius", in reference to Chalcedon (modern Kadıköy, Turkey).
Quality
Buena
Value trend
Estable

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