Petrified wood is a fossil in which the original wood has been replaced by minerals, mostly quartz, while keeping its rings and grain. Silica-rich pieces …
A geode is a hollow, roughly spherical rock – usually formed from a gas bubble in volcanic rock or a cavity in sedimentary limestone – …
This guide brings together everything worth knowing about rockhounding in Colorado — the best sites, the rocks and minerals you can realistically find, and what …
This guide brings together everything worth knowing about rockhounding in Oregon — the best inland sites and beaches, the rocks and minerals you can realistically …
Agate is a banded variety of chalcedony (microcrystalline quartz), built up in fine layers inside gas pockets in volcanic and metamorphic rock, and it typically …
This guide brings together everything worth knowing about rockhounding in Montana — the best sites, the rocks and minerals you can realistically find, and what …
Moonstone is a variety of the feldspar minerals orthoclase and albite, prized for adularescence – the floating, moonlight-like sheen created by microscopic layers of the …