Geyserite
Geyserite is a form of opaline silica that is often found around hot springs and geysers. It is sometimes referred to as sinter. Botryoidal geyserite is known as fiorite.
In May 2017, evidence of the earliest known life on land may have been found in 3.48-billion-year-old geyserite uncovered in the Pilbara Craton of Western Australia.
, Yellowstone
