Orthoclase
Madagascar
12.18 carats
© Rarestone.com
The name derived from Greek "straight fracture" and refers to the two cleavages present in this mineral that meet virtually at right angles to each other.
Orthoclase Gemstones by Colour
This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
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Orthoclase Gemstones by Size
This table shows distribution of Orthoclase 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:0.87 cts
Heaviest:40.13 cts
Average:11.12 cts
Total photos:90
Do you have a larger Orthoclase? Why not upload a photo?
| General Information | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| A variety or type of: | Feldspar | |||||||||
| Varieties/Types: | Adularia - A gemmy colourless variety of Orthoclase. Moonstone - A variety of Orthoclase that exhibits a strong blue adularescence. Sanidine - A triclinic Potassium Feldspar found in lavas. | |||||||||
| Chemical Formula |
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| Physical Properties of Orthoclase | ||||||||||
| Mohs Hardness | 6, Blue Chart Gem Identification (2010) More from other references | |||||||||
| Specific Gravity | 2.54 to 2.61, Blue Chart Gem Identification (2010) More from other references | |||||||||
| Tenacity | Brittle, Gems, Sixth Edition (2006) | |||||||||
| Cleavage Quality | Perfect, Gemmological Tables (2004) More from other references | |||||||||
| Fracture | Uneven, Gems, Sixth Edition (2006) More from other references | |||||||||
| Refractive Index | 1.518 to 1.536, Blue Chart Gem Identification (2010) More from other references | |||||||||
| Optical Character | Biaxial/-, Blue Chart Gem Identification (2010) More from other references | |||||||||
| Birefringence | 0.005 to 0.008, Blue Chart Gem Identification (2010) More from other references | |||||||||
| Pleochroism | Weak, Gems, Sixth Edition (2006) More from other references | |||||||||
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