Anhydrite

Color, clarity, and weight are the decisive factors affecting the price of anhydrite. The price of a tumbled stone around 2.5 cm across is usually $4-$20/piece.

Anhydrite's toughness is poor due to its tendency to cleave easily and its brittle internal structure, making it susceptible to breaking, chipping, or cracking under stress.

Anhydrite's susceptibility to water damage, heat degradation, staining difficulties, and chemical reactivity make it less suitable for daily use where such exposures are common.

A semi-transparent light blue-grey variety from Peru is referred to by the trade name angelite.

Anhydrite is most frequently found in evaporite deposits with gypsum; it was, for instance, first discovered in 1794 in a salt mine near Hall in Tirol. In this occurrence, depth is critical since nearer the surface anhydrite has been altered to gypsum by absorption of circulating ground water. From an aqueous solution, calcium sulfate is deposited as crystals of gypsum, but when the solution contains an excess of sodium or potassium chloride, anhydrite is deposited if the temperature is above 40 °C (104 °F). This is one of the several methods by which the mineral has been prepared artificially and is identical with its mode of origin in nature. The mineral is common in salt basins.

Anhydrite is a sedimentary mineral that has many industrial uses. In the past it was an unwanted side product of synthesizing hydrofluoric acid, but in modern times it has found extensive use as a drying agent. It is added to products like paint, varnish, and plaster.

The name anhydrite was given by A. G. Werner in 1804, because of the absence of water of crystallization, as contrasted with the presence of water in gypsum. Some obsolete names for the species are muriacite and karstenite; the former, an earlier name, being given under the impression that the substance was a chloride (muriate). A peculiar variety occurring as contorted concretionary masses is known as tripe-stone, and a scaly granular variety, from Volpino, near Bergamo, in Lombardy, as vulpinite; the latter is cut and polished for ornamental purposes. A semi-transparent light blue-grey variety from Peru is referred to by the trade name angelite.

The name anhydrite was given by A. G. Werner in 1804, because of the absence of water of crystallization, as contrasted with the presence of water in gypsum. Some obsolete names for the species are muriacite and karstenite; the former, an earlier name, being given under the impression that the substance was a chloride (muriate). A peculiar variety occurring as contorted concretionary masses is known as tripe-stone, and a scaly granular variety, from Volpino, near Bergamo, in Lombardy, as vulpinite; the latter is cut and polished for ornamental purposes.

Anhydrite is believed to facilitate healing from past-life mistakes and allow one to better understand their spirit guides. It is often used to cleanse negative energy, removing all blocks and allowing positive energy to flow through. It may encourage intuitive thinking when placed on the Third Eye chakra and gives the user the insight and energy to make changes as needed.