Labradorite can display an iridescent optical effect (or schiller) known as labradorescence. Some gemstone varieties of labradorite exhibiting a high degree of labradorescence are called spectrolite.
Labradorite ((Ca, Na)(Al, Si)4O8), a feldspar mineral, is an intermediate to calcic member of the plagioclase series. It has an anorthite percentage (%An) of between 50 and 70. The specific gravity ranges from 2.68 to 2.72. The streak is white, like most silicates. The refractive index ranges from 1.559 to 1.573 and twinning is common. As with all plagioclase members, the crystal system is triclinic, and three directions of cleavage are present, two of which are nearly at right angles and are more obvious, being of good to perfect quality.
Metaphysical properties of Labradorite: Labradorite is a stone of transformation.. A great stone for change, for balance and strengthening intuition.