4.1" Polished Baker Ranch Thunderegg with Sagenite - New Mexico

Baker Egg agate (also known as Baker Ranch agate) is a type of agate that formed as thundereggs (lithophysae) from a primarily rhyolite-perlite host rock. They are collected from an area southwest of Deming, New Mexico that was formerly known as Baker Ranch. These thundereggs are unique in that they exhibit vibrant coloration typically only found in agate nodules (amygdaloids).

Thundereggs are rarely found in any other color than white, blue or grey-blue, yet Baker Egg Mine produces mixtures of red, yellow, black, white and, in rare cases, green agate. This is due to the unique geologic history of the area, where rhyolitic lava deposits were disrupted by a mixture of geologic forces and the introduction of basaltic and andesitic lava flows over millions of years. These additional lava flows likely provided the minerals necessary for the variety of coloration found in Baker Egg agates (thundereggs).

Sagenite agate is a formation of agate that contains acicular (needle-like) formations of fanning sagenite crystals encapsulated in a mass of pseudomorphic agate. This occurs when agate fills a cavity within rock that had prior formations of minerals, in this case the golden sagenite crystal clusters.

Sagenite is a name that often refers to acicular rutile crystals, which in this case is accurate. The golden crystals within this specimen are technically rutile (TiO2) crystals.