Agate is the name given to a group of silicate minerals that are made up primarily of chalcedony. Chalcedony is a member of the quartz family of minerals. Like quartz chalcedony is silicon dioxide with a chemical formula of SiO2. Agates are formed primarily in cavities of volcanic rock.Agate is the name given to a group of silicate minerals
What exactly is an agate?
Agate is a banded form of finely-grained, microcrystalline Quartz. The lovely color patterns and banding make this translucent gemstone very unique. Agates can have many distinctive styles and patterns, but each Agate is unique in its own habit, with no two Agates being the same.
Is agate a hard stone?
By Hard Stones, we mean the likes of emerald, sapphire, agate, hard quartz and stones in the Corundum family; essentially, any stone above 7.5 on the Mohs scale. By Soft Stones, we usually mean equal to or lower in hardness than turquoise, rhodochrosite, opal, apatite, fluorite, etc.
Where did agate get its name?
The name derives from Acates, an ancient name for the river Dirillo in Sicily, as the Greeks had searched for the stone along its banks since the fourth century BC. Chalcedony, from the Greek trade city of Kalzedon, is a variety of agate showing layers in grey to brown.
How old is an agate?
Agate is a very old (takes 50 million years to form) and widespread rock that has bands of color on it.
What agates are worth money?
Usually, the most expensive agates by type are landscape agate and fire agate but crazy lace agate, Lake Superior agate, and agate geodes can be quite expensive. Nowadays, you can buy a pound of rough agate for just a couple of dollars (if it isnt a special/rare type).
How do you tell if its an agate?
Inspect the surface of the stone for pit marks. Agates sometimes form in igneous rock and are surrounded by softer rock that erodes away, which can result in surface pitting. Slide your fingers into a crack in the stone or a part of the exterior that has worn away. If you feel waxiness, this is a sign of an agate.