High quality tumblestones at 1-3cm in size. You can either buy these as single stones, or benefit from quantity discounts by purchasing larger amounts.
Labradorite, a feldspar mineral, can display an iridescent optical effect (or Schiller) known as labradorescence. It is an intermediate to calcic member of the plagioclase series. The streak is white, like most silicates. As with all plagioclase members, the crystal system is triclinic. It occurs as clear, white to gray, blocky to lath shaped grains in common mafic igneous rocks such as basalt and gabbro, as well as in anorthosites.
Spectrolite is an uncommon variety of labradorite feldspar, which exhibits a richer range of colors than labradorite. Spectrolite was initially a brand name for material mined in Finland, but is sometimes used to describe labradorite whenever a richer display of colors is present, regardless of locality.