Pyrope

Pyrope is the magnesium-bearing red garnet; its name means “fire-like” in Greek. It is found mostly in rocks that come from deep in the Earth and in the kimberlite that carries them to the surface, which is why it is used as a pointer in diamond exploration. The famous “Bohemian garnets” of Czechia are pyrope. Pyrope cut as a gem always contains some almandine and other garnets.

Jewellery: Red pyropes have been used in jewellery for centuries. Bohemian chromium-bearing pyropes are found even in Migration Period jewellery from about AD 400–600, and in the second half of the 19th century more than 3,000 gem cutters worked in Bohemia. The grains are mostly under 8 millimetres, so Bohemian garnets were cut as small stones. Diamond exploration: Chrome pyropes serve as pointer minerals in the search for diamond-bearing kimberlite pipes, because even if the pipe itself has eroded away, pyrope grains leave a trail in the surrounding sands and gravels.

It has a hardness of 7–7.5 on the Mohs scale. It scratches glass and steel; a steel knife cannot scratch it. Its specific gravity is 3.58–3.87 g/cm³.

Its best-known localities: Dora-Maira massif (Varaita valley), Piedmont, Italy; Kimberley, Northern Cape, South Africa; Třebenice area, Central Bohemian Highlands, Czechia; Pare Mountains and Umba River valley, Tanzania; Buell Park area, Apache County, Arizona, USA.

Crystals can be twelve- or twenty-four-faced; small grains look like red dots in the rock. The colour is red, pinkish red, orange-red or purplish red; some examples look bluish green in daylight and wine red in lamplight. It is very hard to tell from almandine; pyrope usually has fewer flaws and inclusions. A red garnet found in rocks from great depth such as peridotite, kimberlite or eclogite, or in the gravels that come from their weathering, is most often pyrope. Misleading names: “Cape ruby”, “Arizona ruby”, “Colorado ruby”, “California ruby”, “Rocky Mountain ruby” and “Bohemian ruby” have all been used for pyrope garnet; these stones are not rubies.

On the “street to diamond” value ladder it sits on step 5 of nine: Ornamental stone. Colour matters most for pyrope: vivid, blood-red stones are sought after. Chrome pyropes can rival ruby in colour, but their tone is very dark; and since most pyrope looks very dark in large sizes, cut stones over one or two carats are rare. Colour-change pyropes and those in pastel pinks, oranges or purples are less common. Clarity and cut also count, and a historic origin such as “Bohemian” appeals in antique jewellery. Pyrope is usually not treated.

In writings about Bohemian garnets, it is told that a lamp made of garnets lit Noah’s ark in the dark and that knights fitted their weapons with garnets in the hope of protective power. The same accounts say that Bohemian garnet protects friendship and gives courage, confidence and vitality. Today crystal-therapy websites claim that pyrope charges the root chakra with energy and gives passion and creativity. The tale that garnet lit Noah’s ark is a legend; garnet does not shine with its own light, it only reflects the light that falls on it. There is no scientific evidence that pyrope protects friendship, gives courage, vitality or passion, or balances the chakras. This section reports beliefs; it is not health information. There is no scientific evidence for these claims and no stone replaces medical treatment.