Chalcedony

ChalcedonyA silicone based mineral closely related to quartz and agate, Chalcedony has a unique crystalline structure that gives it an enormously variable appearance. This mineral forms in a similar fashion to agates and geodes but due to heat and pressure at the time of formation results in a distinct look and almost silky texture. Chalcedony can be found in a range of colors but most often occurs in semitransparent or white. It has a long archaeological

Also known as antimonite

often including scale and other soft tissue traces against a high contrast laminated limestone slab

521 million years old

This large

from the middle Miocene around 12-16 million years ago

and pure white

Measurement is of box

see photo for small but visible crack in slab

and is one of the more common gems although pieces of exceptional hue and clarity are considered fairly rare and can be extremely valuable

Approx size of fossil - 4

it is largely mined as an industrial ore across the globe

Hyalite is unique in its own right