Despite popular belief, Moss Agate stones don't actually contain moss. Instead, these chalcedony-based stones display inclusions of green-colored minerals that give a grassy or mossy look.
Moss agate is a variety of chalcedony, belonging to the quartz family, and is often found as fragments from weathered volcanic rock formed in fissures or as pebbles rather than in traditional agate layering.
.The colors are formed due to trace amounts of metal present as an impurity, such as chrome or iron. The metals can make different colors depending on their valence (oxidation state)..
