Hardness: 6.00
Refractive Index: 1.51-1.54
Specific Gravity: 2.56
Birthstone:
Astral Stone:
Anniversary Stone:
Origination: Sri Lanka, Myanmar, Madagascar, Brazil and many others
Care & Cleaning: To clean, rub lightly with a soft polishing cloth. If necessary, a plain water rinse may also be used. Do not soak.
Fiction, Facts & Folklore:
Orthoclase is a member of the feldspar mineral group.
Geologists estimate that feldspar covers nearly half of the earth�s land surface.
The moonstone and the adularia are the most famous members of this group.
Like the moonstone, the adularia also exhibits a blue �halo� around its perimeter. This phenomena is known as �adularesence�.
This effect takes on a somewhat different appearance in each of these instances, since the adularia is a clear & colorless gem, while the moonstone is translucent.
Most adularia originates in the majestic Swiss mountains, while the best moonstone comes from Sri Lanka and Myanmar.
The orthoclase is also found in a yellow variety that is often confused with a gem-quality plagioclase feldspar known as labradorite.
Although the casual collector would have much difficulty in telling these two varieties apart, the labradorite has a higher specific gravity than the orthoclase. Thus, the yellow orthoclase would appear to be larger than the labradorite when comparing identical cuts and carat weights. This may help to tell them apart.
The yellow orthoclase from Madagascar is most often a clear, faceted gem, while a lesser-known variety from Germany will sometimes display a cat�s-eye effect when cut en cabochon.