Agate

Agate — is a mineral, a microcrystalline variety of silica. It is fine-fibered aggregating of chalcedony, characterized by its fineness of grain and brightness of color. Jewellers also called varieties of chalcedony without evident stratification, but with various inclusions, creating a specific pattern agate. For example: mocha stone, stellar agate and etc.



Name

The famous scholar of antiquity, Pliny the Elder considered that the name of Agate comes from the river Achates (al-Greek. Ἀχάτης), where the stone had been discovered (now called Dirillo, in Sicily). From another point of view Agate- from the Greek «ἀγαθός» - beneficent, good, blissful. Most often the pattern of Agate looks like eye. One of the ancient legends holds that Agate is the eye of heavenly the white eagle, which after a battle with a black sorcerer fell to the ground and began to stone. And his eyes keep on watching the people, separating the good deeds of evil. Agate is also called the Eye of the Creator.


Physico-chemical properties

Hardness 6, 5 -7.0. Luster on the inflection looks dull greasy or dull, the polished surface - glass. In chemical composition as quartz, a silica, but has mottled structure and with a lot of impurities. Agate is resistant to acids, only etched in HF.

It is robust and tough , nontransparent , translucent at the edges. Most agates alternating layers actually chalcedony and its structural variety - quartzine (lutetium), which differs from calcedony the direction of elongation of ribbons. Chalcedony has perpendicular to the axis of the «C» (direction of elongation of quartz crystals), while quartzine - parallel to or deviation of 30 ° (Lutetium).Visually quartzine layers are usually distinguished by a milky-white color. The color is very diverse, usually dominated by the alternation of blue-gray and white layers. If the white layers of alternating layers of yellow, red, brown, black or another color, then such species may have its own name.


Varieties

  • Fortification Agate (the intersection of the layers and the secondary healed fractures form a pattern reminiscent of images of urban landscapes or bastions);
  • Brazilian Agate (with thin concentric layers);
  • Eye Agate;
  • Blue Agate ("sapphirine");
  • Black Agate ("magic agate");
  • Moss Agate (dendrite - with tree-like inclusions of iron oxides or manganese) ;
  • Wood Agate;
  • Disc Shape Agate;
  • Stellar Agate;
  • Iridescent Agate.

Application

Valuable ornamental and semi precious stone is widely used in jewelry and as a material for carving.


Agate is used in a precision instruments industry. Agate by virtue of his resisting power and viscosity combined with high hardness are made of mortar and pestles for chemical-analytical work, a prism for an analytical balance, hours of stones.