Chemistry: Ca(VO)Si4O10(H2O)4, Hydrated
Calcium Vanadium Silicate.
Class: Silicates
Subclass: Phyllosilicates
Crystal System: Orthorhombic
Cleavage: perfect in one direction
Fracture: conchoidal
Hardness: 3 - 4
Specific Gravity: approx. 2.33
Streak: blue
Luster: vitreous to pearly
Transparency: transparent to translucent
Associated Minerals: zeolites such
as stilbite
and heulandite as well as calcite, apophyllite,
quartz and babingtonite.
PHYSICAL CHARACTERISTICS:
Cavansite is a beautiful and rare mineral, which explains its recent
popularity. It was only discovered in the last 30 years and is found
in only a few localities. It's Color is greenish blue to deep ocean
blue. We have also heard the term electric blue used to describe Cavansite.
Cavansites' Crystal Habits are mainly crystal aggregates that consist
of tufts or spherical rosettes with pointed crystals. These beautiful
blue Cavansite rosettes, mixed among snowey zeolites, make spectacular
crystal specimens. Also some larger crystals show an unusual internal
reflection.
LOCALITIES:
Cavansite was first described as a blue associate of zeolites in 1968
by L.W. Staples. The locality was a road cut near Owyhee Dam, Malheur
County, Oregon.
The best known crystallized Cavansite. Comes from the famous zeolite
quarries of Wagholi, Poona district, Maharashtra, India. The Wagholi
Quarry is a huge basalt quarry.
It was and is, primarily worked for construction materials. But many
wonderful zeolite specimens have made their way out. In recent years,
reports tell of three other quarries in
this region which contain Cavansite.
USES:
At present Cavansite is only used as mineral specimens.
HISTORY & FACTS:
The original Cavansite from Owyhee Dam, Owyhee Co., Oregon. Was a rather
insignificant mineral discovery. It had interesting crystallography
and chemistry. But it was just low-grade Heulandite with pale greenish
inclusions. An unusual blue mineral, later also identified as Cavansite,
began showing up among zeolites from 'Poona' in late 1973. It caused
quite a stir, as the specimens were actually attractive.
The material first came to the Tucson Show in early 1989. It was an
immediate hit, with it's vibrant blue color. Rather than just grains
inter grown in zeolites. The Indian specimens had needle crystals up
to 10 mm long, forming spheres and tufts on white Stilbite. New finds
have repeatedly earned rave reviews.
This area is called the Deccan Traps. It is a famous source of zeolite
specimens, currently the area covers approximately 470,000 square kilometer
in western India, but probably used to cover at least 1.2 million square
kilometers. Most of the Deccan Traps are composed of an Augite basalt
that is chemically and mineralogically extremely uniform. It forms layers
up to 3000 meter thickness in the west around Bombay, but dwindles to
30-150 meter near the rim
The basalt in this area is generally contains few vesicles. The only
reasons for the abundance of zeolites and other minerals from the Deccan
Traps. Are it's immense area and extensive use of basalt for road material.
Unfortunately if there ever was a quarry with abundant vesicles. It
would probably never be worked. A quarries' chief product is road material
and Vesicles depreciate the value of the rock. So it would be abandoned.
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