Artinite is a rare magnesium carbonate found in low-temperature hydrothermal environments as veinlets or crusts along fracture surfaces in serpentinized ultrabasic rocks. Silky, snow-white needles and coalesced balls of pastel-green artinite cover the thin matrix plate on this very rich and showy specimen from the Artinite Pit of San Benito County, California. Ex. John Ydren Collection.