Estilbita
Estilbita is a mineral with formula NaCa₂Al₅Si₁₃O₃₆·14H₂O, in the Silicatos (Zeolitas) group. This specimen comes from Pashan quarries, Pashan, Pune, Maharashtra, India.
Description
Large bow-tie of golden-peach colour and pearly lustre on a very thin basalt plate coated with chalcedony.
History of this specimen
Original double label provided
About Estilbita
Stilbite is a zeolite typical of the basalts of the Deccan Traps, where it fills amygdaloidal cavities alongside heulandite, apophyllite and chabazite. It is a late-stage, cavity-filling secondary mineral. Its crystals form fans or bow-ties with a pearly lustre, a result of its platy habit and hydrated structure. In well-preserved specimens like this, the faces show slight curvature and a warm tone ranging from cream to peach, a hallmark of the Pashan stilbites.
About the locality
The Deccan Traps is a vast basaltic volcanic province formed c. 66 million years ago, contemporaneous with the meteorite impact linked to the extinction of the dinosaurs. Its dense, slow flows generated amygdaloidal cavities that were later filled by hydrothermal waters rich in Ca, Na, Al and Si, crystallising as zeolites such as stilbite. Between the 1970s and 1990s numerous zeolite specimens entered international trade, making Pune synonymous with quality within this mineral group. Today most quarries are inactive, mainly because urban expansion has built over them, so pieces with old labels, like this, almost always come from collections formed in the first exchanges with local collectors.
Technical data
- Catalogue No.
- 0264
- Composition
- NaCa₂Al₅Si₁₃O₃₆·14H₂O
- Name
- Estilbita
- Group
- Silicatos (Zeolitas)
- Category
- Meritum Persé
- Matrix
- Calcedonia
- Mine
- Pashan quarries
- District / Municipality
- Pashan
- Province
- Pune
- Region
- Maharashtra
- Country
- India
- Size (cm)
- 8 x 3.5 x 3
- Weight
- 93.4 g
- Ex-collection
- Sergio Petretich
- Etymology
- From the Greek "stilbein", to shine, in reference to its characteristic pearly lustre.
- Quality
- Muy buena
- Value trend
- Estable
Related specimens
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