Labradorite
is the plagioclase feldspar most commonly faceted as a gem.
It occurs in orange, yellow, colorless, and red, but the material
that shows a play of color, or "schiller", is the most popular
for use in jewellery.
Occurrence
Occurs in metamorphic and igneous rocks in Labrador (Canada), Finland, Norway, and the former USSR.
Remarks
Kyanite
crystals have two values: they are softer parallel to the
direction of cleavage, and harder perpendicular to it.
Labradorite 
