Grape Agate Chalcedony Tumblestone Large AAA+

£4.99

Grape Agate Chalcedony Tumblestone large Approx 30mm. Beautiful and very unusual stones. I?ve only ever seen mineral specimens before, not shaped pieces. Lovely open geode on both sides.

Grape Agate

Grape Agate gemstone is a relatively new find. Although the trade name is Grape Agate, these are actually Botryoidal Purple Chalcedony. Botryoidal means that round tiny sphere shaped crystals that have naturally formed together. Grape agate is a tranquil and gentle stone.

Chalcedony is not scientifically its own mineral species, but rather a form of Quartz in microcrystalline form. Chalcedony is a cryptocrystalline form of silica, composed of very fine intergrowths of quartz and moganite.

Chalcedony has a waxy luster, and may be semitransparent or translucent. It can assume a wide range of colors, but those most commonly seen are white to gray, grayish-blue or a shade of brown ranging from pale to nearly black.

Chalcedony is quite varied in its formation habits. It sometimes occurs in geodes, lining the cavity with mammilary blobs. Its Agate variety is also found in geodes, commonly lining the outer layer underneath the larger Quartz crystals. Chalcedony also forms pseudomorphs after organic material.

A well-known example is petrified wood, in which the wood has been completely transformed into Chalcedony. In the Petrified Forest National Monument in Arizona, an entire forest was transformed into petrified wood. Remains of this ancient forest can be seen in the huge silicafied logs that are found in the area.