Mohs Hardness of 7 with a trigonal crystal structure.
Agates occur in nodular masses in rock such as volcanic lavas. When split open, they often reveal an amazing variety of colors, patterns and a beautiful distinct banding that distinguishes the Agate from other forms of Chalcedony.The mining of Agate in the Nahe River valley in Germany was documented in 1497, which gave rise to the cutting center of Idar-Oberstein, Germany. Originally, the river was used to power the grinding wheels. When the Nahe Agate deposit was exhausted in the nineteenth century, Idar cutters started to develop the agate deposits of Brazil, which also sparked exploration and discovery of Brazil’s rich deposits of amethyst, citrine, tourmaline, topaz, and other gemstones.X