Detailed Product Description

Labradorite ((,)(,)₄₈), a , is an intermediate to calcic member of the series. It is usually defined as having "%An" () between 50 and 70. The ranges from 2.71 to 2.74. The streak is white, like most silicates. The ranges from 1.555 to 1.575. is common. As with all plagioclase members the crystal system is and three directions of are present two of which form nearly right angle prisms. It occurs as clear, white to gray, blocky to lath shaped grains in common such as and , as well as in .

The geological type area for labradorite is near the town of in , . It occurs in large crystal masses in anorthosite and shows an or play of colors. The iridescence is the result of light within lamellar intergrowths resulting from phase exsolution on cooling in the Boggild gap, An₄₈-An₅₈.

varieties of labradorite exhibiting a high degree of iridescence are called ; and are also commonly used terms, and high-quality samples with good iridescent qualities are desired for jewelry.