Photo of Pyrope in Processed & Rough Form
Pyrope is a mineral with a hardness of 8 out of 10 on the Mohs scale of mineral hardness [?]. These Cubicly structured gems are made of magnesium aluminum silicate, their full chemical compound being Mg3Al2(SiO4)3.
Pyrope is the iron magnesium and aluminum silicate of the pyrope-almandine series in the Pyralspite group of the Garnet family. Its beautiful deep-red gem quality makes it one of the most popular. Pure pyrope is colorless, but its red color, sometimes very bright, is due to small quantities of chrome in the crystal structure.
It appears as dodecahedral or trapezohedral crystals, dark red, usually very well-formed. It also occurs as rounded grains. As isolated, granular crystals, it often appears in the form of a perfect rhombic dodecahedron. The color is often reddish brown, but can be a definite red, light red, violet red, or deep blackish red. The crystals, which are often semiopaque, can be transparent and limpid, with highly lustrous faces.
It is very hard, heavy, has no cleavage, but breaks into splinters. It is often transparent, with vitreous luster. It fuses fairly easily and is practically insoluble in acids, and has the lowest density of all the garnets.
Unlike other garnets the most common origin of pyrope is igneous rather than metamorphic. It is typical of peridotites and serpentinized peridotites. It also occurs associated with diamond in kimberlite deposits (and is an inclusion mineral in diamond), and concentrated in placers. Due to their resistance to weathering, pyrope and almandine are often found in alluvial, secondary deposits or arenaceous rocks.
Splendid blood-red crystals are found in Bohemia (Czechoslovakia), Dora
Maira Massif, Western Alps, (Italy), and South Africa. Lighter-colored specimens from Canton Ticino, Switzerland (Gorduno), Arizona and New Mexico (USA), and Scotland (called "Elie ruby").
It is also called "carbuncle," "Bohemian garnet," "precious garnet,"
Varieties of pyrope include:
Rhodolite - the rose-red or pale variety of pyrope. This variety derives its name from the mountain rhododendron (Rhododendron catawbiense), a magenta-colored bloom which grows in the mountains of North Carolina.
Raspberry Rhodolite - this material is called "raspberry" because its fine purplish pink color resembles that of the fruit.
Cranberry Rhodolite = pinkish red rhodolite found in Nigeria, is mostly high quality cabochon grade as most stones tend to be very slightly to moderately included.
Cherry Rhodolite = found in the Umba River Valley region of Tanzania and displays a bright cherry-red color.
Grape Garnet - the original purplish red to violet garnet mined in the Orissa state of North-west India and known as grape garnet has been variously reported as an intermediary between both spessartine and almandine and pyrope and almandine. However, published chemical data states that these contain >50% pyrope molecule.
Malaya (Malaia) Garnet - The dark brownish red pyrope-spessartine-grossular combination. The name "malaya", a Swahili word meaning "out of the family", came to be used for garnets that did not fit the color requirement for rhodolite or because of the properties, did fit into traditional garnet categories. Malaya is an intermediate between spessartine and pyrope, originally from the Umba River valley in Tanzania. The colour of malaya ranges from yellowish brown and brownish pink through a cinnamon to a crisp honey brown and reddish brown to a brick or brown orange.
Arizona Chrome Pyrope (Anthill) Garnet - In color saturation, there is only modest comparison to normal pyrope. The Anthill garnet has a rich red hue described as ruby red with purple to orange highlights.
Crimson Garnet - A deep red-colored pyrope-spessartine-almandine garnet, with flashes of orange, discovered near an area called Tiriri in North-east Tanzania is being marketed as crimson garnet.
Blue Garnet - In daylight, color change pyrope-spessartine garnets from Bekily, Madagascar, have been described variously as blue, grey-blue and greenish blue.
The specific gravity [?] for Pyrope is 3.8, its refractive index [?] is 1.72-1.76, and its double refraction [?] is None.
History
Pyrope was named by Werner in 1803 from the Greek "pyropos," meaning "fiery" and is similar to the Latin name "carbunculus" (small coal or ember), attributed to all red transparent stones.
The name "garnet," from the Latin "malum granatum," now applied to an entire family of minerals, was originally given to the garnets of the Pyrope-Almandine series, due to their resemblance to red pomegranate seeds.
Pyrope was the fashion stone of the 18th and 19th centuries. In the latter half of the nineteenth century, most pyrope came from Bohemia, where it is still found today. Main sources today are the USA, Mexico, Brazil, Argentina, and Australia.
Industrial Usages
Pyrope's clear, uniformly colored crystals are used as gemstones. When used in jewellery, it is often given incorrect names, such as "Cape ruby," "Bohemian ruby," "Arizona ruby" or "Arizona spinel."
Usually bright red, pyrope can be a much less attractive brick or dark red. It can be perfectly transparent, but this feature is less visible in dark specimens. It is either made into fairly complex cabochons, or faceted, with an oval or round mixed cut, or more rarely, a step cut.
The faceted gems have good luster, less obvious in cabochons. The most valuable types are the transparent ones with the brightest red color.
It is singly refractive, and has a luster comparable to that of ruby and spinel. It is distinguished from ruby by a lack of pleochroism, and the fact that is does not turn bright red in strong light; but it can only be distinguished from spinel by measuring its physical characteristics.
Pyrope is relatively common, although less so than almandine. Very large stones, up to several hundred carats, have been found; but these are rare and are found in museums and famous collections.
It is of quite low value as secondary gems go, probably due to its abundance. The darkest specimens, which are the most common, are worth very little. While even in early times pyrope could be distinguished from ruby because of its relative softness, it was more highly valued then than it is today, probably because of it color.
Formerly, when it was more highly prized, pyrope was imitated by glass, which can look very similar, but does not have the same hardness. It is not produced synthetically.
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