Petrified Slice of Colla Wood

Colla wood is a rare type of petrified wood that can only be found near the Black Sea town of Zile, Turkey. Having fossilized over an active copper deposit, copper-containing minerals such as azurite, malachite, and chrysocolla (hence the name "colla wood") have absorbed into the wood, slowly replacing the original organic material and creating vibrant streaks of blue and green. Several other minerals, such as chalcedony and hematite, can produce red, brown, and white accents in colla wood, as seen in the specimen offered here.