River Agate Bahia 1 Piece Raw Minerals Stones Rocks Collecting (4)

Description

Origin : Brazil

River Agate or Agate Bahia 1 Piece 41-50 - cm 3.5-5 Raw Minerals Stones Rocks for Collection.

Agate (from the ancient Greek: ἀχάτης, achátes) is a variety of Chalcedony, a generic name given to Quartz, when it occurs in compact masses of microcrystalline silica with a fibrous-oriented texture. Agate has a typical zoned structure and is visible even to the naked eye, thanks to the diversity of color.
Agate is formed by rhythmic deposition of silica, usually within amygdalar cavities of basaltic rocks, or petrified (agatized) woods.
There are different varieties of agate: band, fortress, eye, dendritic, musky, etc.
When the agate is presented in flat and parallel bands, of a contrasting color (light / dark), it takes the name of onyx (from the Greek ὄνυξ, ónyx, nail, due to its translucent appearance).
According to the colors of the bands, there are different denominations: brown background layer: sardonyx; red base layer: onyx-carnelian.
One of the most famous deposits is that of Idar-Oberstein, in Rhineland-Palatinate, where agate has been collected since 1548. Other large deposits are present in Uruguay and Brazil.
Agate is used in jewelry and is also used in industry, due to its hardness, in the production of mortars or textile chains.