Prehnite
Prospect Quarry, Prospect Hill, Prospect, Cumberland County, New South Wales, Australia
4.2 carats
© LucianaBarbosa.com
Individual crystals are rare. Faceted gems are seldom fully transparent and don't show "fire". Prehnite is usually cut into cabochons or carved.
Extensive deposits of gem quality prehnite occur near Wave Hill Station in the central Northern Territory, of Australia.
Prehnite cat's is known.
Prehnite Gemstones by Colour
This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
 |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Prehnite Gemstones by Size
This table shows distribution of Prehnite gemstone sizes that are listed on this site. This can give a good indication as to the general availability of this gemstone in different sizes.
Contributed photos
Lightest:1.11 cts
Heaviest:40.17 cts
Average:8.70 cts
Total photos:54
Do you have a larger Prehnite? Why not upload a photo?
| General Information | ||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chemical Formula |
| |||||||||||||||||||||
| Physical Properties of Prehnite | ||||||||||||||||||||||
| Mohs Hardness | 6 to 6.5, Blue Chart Gem Identification (2010) More from other references | |||||||||||||||||||||
| Specific Gravity | 2.80 to 2.95, Blue Chart Gem Identification (2010) More from other references | |||||||||||||||||||||
| Tenacity | Brittle, Blue Chart Gem Identification (2010) | |||||||||||||||||||||
| Cleavage Quality | Good, Gemstones of the world (2001) More from other references | |||||||||||||||||||||
| Fracture | Uneven, Gemstones of the world (2001) More from other references | |||||||||||||||||||||
| Optical Properties of Prehnite | ||||||||||||||||||||||
| Refractive Index | 1.611 to 1.673, Blue Chart Gem Identification (2010) More from other references | |||||||||||||||||||||
| Optical Character | Biaxial/+, Blue Chart Gem Identification (2010) More from other references | |||||||||||||||||||||
| Birefringence | 0.021 to 0.039, Gemstones of the world (2001) More from other references | |||||||||||||||||||||
| Pleochroism | Absent, Gemstones of the world (2001) More from other references | |||||||||||||||||||||
| Dispersion | None, Gemstones of the world (2001) More from other references | |||||||||||||||||||||
| Chatoyancy | Yes, Gemmological Tables (2004) | |||||||||||||||||||||
| Colour | ||||||||||||||||||||||
| Colour (General) | Oily yellowish-(greenish), Blue Chart Gem Identification (2010) More from other references | |||||||||||||||||||||
| Transparency | Translucent, Blue Chart Gem Identification (2010) Usually translucentMore from other references | |||||||||||||||||||||
| Lustre | Vitreous,Pearly, Blue Chart Gem Identification (2010) More from other references | |||||||||||||||||||||
| Fluorescence & other light emissions | ||||||||||||||||||||||
| Fluorescence (General) | None, Gemstones of the world (2001) | |||||||||||||||||||||
| Crystallography of Prehnite | ||||||||||||||||||||||
| Crystal System | Orthorhombic, Blue Chart Gem Identification (2010) More from other references | |||||||||||||||||||||
| Habit | Radiating fibrous aggregate, Gemmological Tables (2004) More from other references | |||||||||||||||||||||
| Geological Environment | ||||||||||||||||||||||
| Where found: | Occurs as a secondary or hydrothermal mineral in veins or cavities in mafic volcanic rocks or in granite gneisses or syenites, Gems, Sixth Edition (2006) | |||||||||||||||||||||
| Further Information | ||||||||||||||||||||||
| Mineral information: | Prehnite information at mindat.org | |||||||||||||||||||||
| Significant Gem Localities | ||||||||||||||||||||||
| ||||||||||||||||||||||