The chemical formula of mineral Pyrope is indicated by Mg3Al2(SiO4)3 or Magnesium Aluminum Silicate. Pyrope is actually a Silicate mineral. Pyrope is most commonly used as abrasive and it is also used for gemstone purposes. Pyrope is the only garnet that is always a shade of red. Pyrope is a common gemstone although it is less common than most other garnets. Pyrope is the only garnets whose most common source is igneous rather than metamorphic. Most Pyrope comes from ultramafic igneous rocks that contain olivine and/or diamond. Metamorphic Pyrope comes from the metamorphism of the igneous rocks previously mentioned or from magnesium rich rocks subjected to high grade metamorphism. Almandine and Pyrope form a series in which iron substitutes for the magnesium in Pyrope. In fact, pure Pyrope is unknown in nature and the various proportions are referred to as Pyrope-Almandine mixes. One mixture of approximately two to one is a variety called rhodolite which has an attractive red-lavender color and is cut as a gemstone. Pyrope is difficult to distinguish from almandine but is usually clear and free from flaws, at least more so than almandine.
Pyrope is most commonly found red to reddish purple and sometimes a deep enough red to appear black that could appear more splendidly exhibited when viewed with the aid of polarizing light microscope used in optical mineralogy. Pyrope is also most commonly found exhibiting vitreous luster when viewed in reflected light of petrographic polarizing microscope used in optical mineralogy. Most crystals of mineral Pyrope are found transparent to translucent in appearance. Pyrope is known to crystallize in the isometric system of crystal formation. In optical mineralogy, this isometric crystal system comprises crystals having three axes, all of which are perpendicular to one another and all are found equal in lengths. The crystal system of mineral Pyrope as described in the field of optical mineralogy includes the typical rhombic dodecahedron. It is also seen in 24-sided trapezohedron. Combinations of these forms are common and sometimes the rare faces of the hexoctahedron, a 48 sided crystal habit that rarely is seen by itself, can also combine with these other forms making very attractive, complex and multifaceted crystals. Massive and granular occurrences are also commonly. Pyrope has absent cleavage even when viewed under polarizing microscopes used in optical mineralogy. It also exhibits conchoidal fracture when viewed with the aid of polarizing light microscopes. The hardness measure of mineral Pyrope when it is evaluated using the Mohs scale method is usually ranging from 7 to 7.5. Pyrope is most commonly found leaving a white streak when specimen is rubbed on a white porcelain streak plate. The specific gravity measure of mineral Pyrope is approximately 3.6grams per cubic centimeters, which is considered above average for translucent minerals. Pyrope is most commonly found associated with other interesting mineral including olivine, biotite, augite, serpentite, olivine, hornblende, pyroxenes and diamond. The index of refraction shown by mineral Pyrope is usually 1.73. The best field indicators of mineral Pyrope usually include color, crystal habit, environment, and hardness. Pyrope notably occurs at several localities including Europe, Arizona and New Mexico in USA, South Africa and several Australian sites.
