Howlite is a soft, light gemstone with a chalky white color, commonly with black or brown veins. Crystals are occasionally found in groups. It is very porous and could be dyed to imitate other gemstones, especially turquoise.
Howlite has been found in large quantities in California (USA).
Even though it is soft, howlite will withstand a polish, and is occasionally used as a decorative stone.