Also if the viewer does not observe from the precise angle or if light is not supplied from the proper angle then no color shiller is seen. The labradorescence is truely a one of a kind mineralogical experience and must be observed in person in order to truely appreciate its beauty. Labradorite is a member of the plagioclase series of minerals. CaAl 2 Si 2 O 8 . The twinning is caused by a error in the crystal structure during its growth.
Color is gray to smoky black.
Luster is dull to vitreous. Transparency crystals are transparent to translucent. In sliced sections of rock, the labradorite appears as blocky chunks with a predominance of near right angled corners. Twinning is common and pervasive so that in labradorite it produces a layered or stacked effect. The twin layers are typically only fractions of millimeters to several millimeters thick.