Natural Blue Flash Black Labradorite Micro Faceted Tear Drop Briolette Drop Beads Strand Length 9 Inches and Size 7.5mm to 9.5mm approx. Labradorite a feldspar mineral, is an intermediate to calcic member of the plagioclase series. Labradorescence is a side-effect of the molecular change which occurs in large crystal masses of anorthosite, producing an iridescent play of colors.