Agate

The name agate is derived from a river in Sicily, the Achates.

Agate is one of the group of crystals. Its Mohs hardness is 6.5-7. Like all quartz agate is silicon dioxide.

Agate is a concentric-shelled, striped chalcedony, which may well be crossed by Opalsubstanz. These ribbons are color coded or monotonous. The agates were found in Germany, pink, red and brown with gray liners. The agates, which are promoted in South America are usually gray and without striking
Drawing. Nevertheless, here today, the most important development areas (Uruguay, Brazil). This greyish agate can be chemically treated and are thus nachgefärbt in general. The Romans knew of the agate dyeing techniques.

Amethyst Geode

Agates are found as almond-shaped  or spherical inclusions in so-called geodes. These are partially or completely filled cavities. You can size from a few millimeters to several meters in scope. The striped pattern formed by rhythmic crystallization. The exact procedure is controversial. The individual agate bands vary in thickness. They retain their strength but usually in throughout the Geode. The interior of the Geode not completely filled with agate mass can thus formed in the cavity formed crystals. These are mostly rock crystal, amethyst or smoky quartz.