Howlite

Howlite was discovered near Windsor, Nova Scotia in 1868 and named after Henry How, a Canadian chemist, geologist, and mineralogist.
It often forms in nodules which resemble cauliflower heads. The nodules are opaque, white with gray or black veins, often showing web-like pattern. Crystals are very rare and are found in only a couple localities in the world. The maximum size of crystals is about 1 cm.
Howlite is used for cabochons, decorative objects, beads, small carvings or jewelry components. Dyed blue howlite is used as a turquoise substitute and is sometimes marketed as turquenite.