Agate
Agate was called for the Achates River, Acate, Ragusa Province, Sicily, Italy by Theophrastus, a Greek philosopher and naturalist, whom discovered the rock along the coast associated with river Achates sometime between the 4th and centuries which are 3rd. This river is now called the Dirillo river and agates that are colorful other Chalcedonies can nevertheless be discovered there.
Agate is a distinctly banded variety of Chalcedony which is really a number of Quartz. Chalcedony is a translucent variety of cryptocrystaline, or fine-grained, Quartz with a microstructure that is fibrous. Agate is characterised by its concentric (having the center that is exact same axis) banding which may be fairly easy or wildly patterned and often vibrant colored by many different types of impurities. Agate has variety that is many according to colors, locations and patterns. Several of the most varieties that are common Blue Lace Agate, Botswana Agate, Brecciated Agate, Crazy Lace Agate, Fairburn Agate, Fortification Agate, Laguna Agate, Lake Superior Agate, Mexican Lace Agate, Nipomo Agate, Pigeon Blood Agate and Plume Agate.
Chalcedony includes subvarieties that are many as the numerous varieties of Agate, Binghamite, Bloodstone, Carnelian, Chrysoprase, Onyx, Pietersite, Petrified Wood, Sard and Sardonyx. When Chalcedony is concentrically banded the subvariety calls it name Agate. It really is called by the subvariety name Onyx when it’s in flat layers or bands of black colored and white. It is known as by the subvariety name Sardonyx whenever it is in flat layers or bands of light and dark shades of reds, browns and white.
Many non-banded forms of Chalcedony – such as Moss Agate, are usually mistakenly called ‘Agates’. Real Agate is concentrically banded. Included and mottled chalcedonies are more properly simply called ‘Chalcedony.’ Petrified Wood (agatized timber) could be the name directed at fossil lumber where the replacement of the timber is by Chalcedony, but the banding in this situation is due to the wood framework or growth rings – maybe not concentric deposition of the Chalcedony – together with material is Chalcedony, not real Agate.
Agate is available from many sources global.
| Chemical Formula: | SiO2 (Quartz) + impurites |
|
Silicon Dioxide + impurites |
|
| Crystal System : |
Rhombohedral Microcrystalline |
| Color: |
White to grey, light blue, orange to red, black. |
| Luster: |
Waxy |
| Refractive Index: |
1.530–1.540 |
| Specific Gravity: |
2.58–2.64 |
| Hardness: |
6.5–7 |
| Fracture: |
Conchoidal with very sharp edges. |
| Birefringence: |
pto +0.004 (B-G) |
| Pleochroism: |
Absent |
| Cleavage: |
None |
