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Saturday, April 29, 2017

Pyrope

What is Pyrope?

Pyrope is the most well-known gemstone form of Garnet. The term Garnet describes a group name for several closely related minerals that form important gemstones, and Pyrope is an individual member mineral of the Garnet group. Its dark, blood-red colour is distinct and attractive, and makes a fine Garnet gemstone. In the gem trade, the term Pyrope is rarely used on its own. It is either generically called "Garnet", or "Pyrope Garnet".
The mineral pyrope is a member of the garnet group. Pyrope is the only member of the garnet family to always display red colouration in natural samples, and it is from this characteristic that it gets its name: from the Greek for fire and eye. The composition of pure pyrope is Mg3Al2(SiO4)3, although typically other elements are present in at least minor proportions-these other elements include Ca, Cr, Fe and Mn. Pyrope forms a solid solution series with almandine and spessartine, which are collectively known as the pyralspite garnets (pyrope, almandine, spessartine). Iron and manganese substitute for the magnesium in the pyrope structure. The resultant, mixed composition garnets are defined according to their pyrope-almandine ratio. The semi-precious stone rhodolite is a garnet of ~70% pyrope composition.
The origin of most pyrope is in ultramafic rocks, typically peridotite from the Earth's mantle: these mantle-derived peridotites can be attributed both to igneous and metamorphic processes. Pyrope also occurs in ultrahigh-pressure (UHP) metamorphic rocks, as in the Dora-Maira massif in the western Alps. In that massif, nearly pure pyrope occurs in crystals to almost 12 cm in diameter; some of that pyrope has inclusions of coesite, and some has inclusions of enstatite and sapphirine.
Pyrope is common in peridotite xenoliths from kimberlite pipes, some of which are diamond-bearing. Pyrope found in association with diamond commonly has a Cr2O3 content of 3-8%, which imparts a distinctive violet to deep purple colouration (often with a greenish tinge) and because of this is often used as a kimberlite indicator mineral in areas where erosive activity makes pin pointing the origin of the pipe difficult. These varieties are known as chrome-pyrope, or G9/G10 garnets.

History and Introduction

Pyrope garnet is the best known of the red garnets. It has a distinctive red colour that often resembles the colour of ruby or pomegranate seeds. The word "pyrope" comes from the Greek word "puropus", made up of "pur" (fire) and "ops" (eye) meaning "fiery-eyed". This refers to the impressive brilliance of pyrope garnet, which is a result of its high refractive index.
The use of red garnet dates back thousands of years, when it was used by Egyptian pharaohs for both decorative and ceremonial purposes. The ancient Romans also wore garnet rings and traded garnet gemstones. In ancient times, garnet and other red gemstones cut en cabochon were called "carbuncles", which is not the prettiest of names because it was also used to define pus-filled boils. Nowadays, any natural red gemstone cabochon can be traded as carbuncle stones.
The Latin word, "carbunculus" alludes to a burning piece of coal or ember. This may have been used to refer to garnet because of its bright colour large deposits of pyrope garnet were discovered in Bohemia (Central Europe) around the 16th century, which became the focus of the jewellery industry in the area. Bohemian pyrope garnet from the Czech Republic continues to be mined today.

Identifying Pyrope Garnet

Pyrope garnet is magnesium aluminium garnet. Iron can substitute for the magnesium and become more like almandine, which is iron aluminium garnet. Pure pyrope and pure almandine are rare in nature and most specimens are a mixture of the two. The change in density from almandine (4.3) to pyrope (3.6) is the only good test to determine a specimen's likely identity. Garnet can be distinguished from other gem types by its occurrence in metamorphic rock, its hardness (6.5 - 7.5 on the Mohs scale), colour, refractive index and cubic crystal structure. However, the quickest way to identify garnet is with the use of strong neodymium magnets. Garnet is attracted to neodymium magnets because it contains high concentrations of iron and/or manganese.

Origin and Gemstone Sources

Pyrope garnet sources include China, Madagascar, Myanmar, South Africa, Sri Lanka, Tanzania and the United States. Deposits in the Czech Republic do still exist, but are of minor importance.

Determining Pyrope Garnet Gemstone Value

Pyrope Garnet Colour

The characteristic dark-red of pyrope garnet is found in small sized stones. Bigger gems tend to be very dark, coming close to black.

Pyrope Garnet Clarity and Luster

Pyrope garnet is often inclusion free, so buyers should seek an "eye clean" stone. Pyrope garnet has a beautiful glossy vitreous luster.

Pyrope Garnet Cut and Shape

Pyrope garnet is versatile and can be cut into a wide variety of shapes. Pyrope garnet is not often seen in large sizes. It can be faceted or cut en cabochon. Faceted cuts best exhibit the beauty of pyrope garnet.

Pyrope Garnet Treatment

Pyrope garnet is not known to be treated or enhanced in any way.

Pyrope Metaphysical and healing properties

Pyrope Garnet offer us physical, emotional and spiritual support. Use its healing powers to boost circulation and blood disorders, as well as the digestive tract and immune system. Pyrope emotionally relieves anxiety, and promotes composure, courage and endurance. It lightens the overall mood. It protects the Base and Crown Chakras, and may balance the Heart and Brow Chakras as well.
Pyrope Garnet stimulates warmth and gentleness, unifying the creative forces of the self. On the spiritual path, it also helps open the heart to love - from Divine Love, as well as love of others.
Pyrope Garnets range in colour energies from rose red to deep crimson, including shades of scarlet, amethyst and indigo. It attracts a host of Angels and honours four Goddesses.
Garnet is the traditional birthstone of January, and Pyrope, in various hues, is a natural birthstone for many born at the end of summer through the winter. It is the zodiac stone for those born under the sign of Aquarius and it brings you Fire energy. As an Enhancer Strengthener crystal, it is a talisman of protection.

Properties of Pyrope

Chemical FormulaMg3Al2Si3O12
ColourRed
Hardness7 - 7.5
Crystal SystemIsometric
Refractive Index1.720 - 1.760
SG3.5 - 3.6
TransparencyTransparent to translucent
Double RefractionNone
LusterVitreous
CleavageNone
Mineral ClassPyrope (Garnet)