What is Agate?
- Agate is a variety of Chalcedony which is a member of the Quartz family.
- There is a vast range of stones that come under the heading of Agate. Scientifically it is the banded stones that are considered true Agates, however stones with dendritic inclusions of various other minerals, such as Tree Agate have found their way into this group.
- The natural colours of banded Agate are white, grey, red, brown, black and the soft blue of Blue Lace Agate, all beautiful in their own right. There is sadly a huge trend at present to dye Agates vivid colours with organic and inorganic dyes, which creates a toxic waste water problem in the areas of production.
How is Agate formed?
- Agate has a trigonal crystal system and a hexagonal structure. Agate has a hardness of Mohs 7.
- Agate is generally formed when deposits of silica rich matter fill volcanic cavities, although it can be found in other rock formations too. Agate's appearance is dictated by the locality in which is was formed and what type of minerals are found there.
- Banded Agate is formed by silica rich water that has penetrated volcanic rock cavities, laying down layers of mineral salts often in concentric patterns, these minerals harden over time forming the banding. Sometimes the liquid doesn't entirely fill the cavity and leaves a hollow void in which crystalline Quartz forms into a sparkly inner core of druzy.
- Types of dendritic Agates inclued Tree Agate, Moss Agate and Merlinite. Although the fern like patterns in dendritic Agates look organic as if some ancient plant material has become trapped within the Chalcedony, the formations are actually made from traces of iron and manganese that have seeped from nearby rocks into any fine fractures within the stone as it was forming.
Where is Agate found around the planet?
- Agate is a common stone and is found widely across the planet although it's location will dictate it's appearance.
What is the history and folklore of Agate?
- Agate gets it's name from the Achates River in Sicily, Italy (now known as the Dirillo River), where a Greek philosopher and naturalist by the name of Thoephrastus found it on the shore line around 400 BC.
- Agate has been found in archaeological digs that date back to the bronze age.
- Throughout the ages Agate has had a reputation as a stone of protection, this banded mineral was worn in the breast plates of ancient warriors, as they believed it would give them courage, strength and protect them in battle.
- In Italy and Persia Agate has a reputation for protecting against the evil eye.
How do I care for Agate?
- Agate is a hard stone and can be wiped over with a soft damp cloth.
- If your Agate has a druzy inclusion you can gently clean in the crevices with a very soft toothbrush.
- The colours in Agate can fade if it is left in direct sunlight for long periods of time.
- Agate is a brittle stone and may fracture if it suffers a sudden change in temperature.