Moss Agate

Moss agate is a natural variety of chalcedony (microcrystalline quartz, SiO₂): a colorless to white, translucent stone containing green, moss-like inclusions of minerals such as chlorite or hornblende, sometimes with brown to black dendrites of iron or manganese oxides. Despite the name it is usually not banded like a true agate. Mindat lists tree agate and medfordite as synonyms; "mocha stone" is an older name used inconsistently by vendors.