Jewelry Lovers

The beguiling luster of this attractive gemstone—shining like damp moss in autumn sunshine—earned peridot the sobriquet of “green gold.” In earlier times it was readily linked with the sun, of whose bright rays it was said to be the keeper and therefore alleged to be a shield against the threat of eclipse and blindness of the eyes. Peridot belongs to the olivine family, whose aristocratic representative it is. Here we meet a second gemstone, like garnet, which is a member of an isomorphous series of mixed crystals. By this is understood the property of interchanging inherent elements without altering the crystal structure. Peridot stands approximately in the middle of such a series, flanked by two unprepossessing minerals as end members. The iron content is critical, since it belongs as the idiochromatic coloring agent in the chemical composition. It is a magnesium iron silicate, in which magnesium and iron are combined with silica in varying proportions. At the low-iron end of the mixture series stands the colorless forsterite and at the iron-rich end the black fayalite. Peridot therefore acts as the central link member of the olivines which, although they are very important rock-forming minerals of the basic magmas of the sima, only attain gem quality in rare cases.

Peridot is an early crystallization, formed during the solidification of igneous rocks in the liquid magmatic phase. As a microscopically small crystallite, it even participated decisively in the formation of diamonds. In kimberlite, its ultimate mother rock, peridot is a constituent component, which, in the primary diamond deposits of South Africa, is also responsible for the bluish-green color of the “blue ground.”

On the barren desert island of Zebirget (St. John) in the Red Sea, the former classical source of peridot, it is embedded in a plutonic rock called gabbro, which crystallized extremely slowly from great molten masses in the depths of the earth. Thus very large and undisturbed crystals were able to develop, which were typical of Zebirget and for which the island was famed for thousands of years. In fact, peridot is one of mankind’s long familiar gemstones. Even 1500 years before the birth of Christ it was hewn by Egyptian slaves out of its dark matrix on the little island; the ancient Egyptians, who knew it under the name of topazion, prized it especially as a jewel stone, used mainly for ear pendants.

The island, often enveloped in mist, was difficult of access, whence sailors named it topazion, derived from the Greek verb “to seek.” For centuries it bore the simple name topaz, until slowly the French name peridot (which comes from the Arabic word faridat = gemstone) superseded it. The magnificently shaped crystals were first brought by the Crusaders to Central Europe, where their special suitability for sacred purposes was soon recognized. Indeed, in the church history of medieval times, when it was used to decorate altars, it was almost indispensable.

In Hawaii peridot is interspersed in a fine-grained, massive basalt, from whose dark groundmass the olive green crystals stand out clearly. Recovery is not possible from the basalt itself owing to the great hardness of the rock. Moreover, the average size of the crystals amounts to only a few carats. Near Hilo in Hawaii, however, small peridots are also found in a secondary deposit of fine black sand, derived from the basalt. These stones, too, are small but, thanks to the natural sorting process, mostly good cuttable specimens have been preserved.

After Hawaii, which strews its peridot carelessly as green grains on the sandy shore, the most prolific source today is found a few kilometers north of Mogok, the legendary valley of rubies in Burma, on the north slope of the 2,2 50-meter high mountain Kyaukpon. In contrast to rubies, sapphires, spinels, and many other gemstones with which the Mogok valley has blessed us, peridot is not found in gem gravels. It crops out sprinkled as small- to medium-sized shining green crystals in a loose, weathered greenish serpentine resulting from the metamorphism of a ferruginous gabbro. Like glimmering owl’s eyes, bright well-shaped crystals of peridot blink here and there from the hydrated serpentine.

The probably hydrothermal metamorphism of the former plutonic rock altered only the mother rock without attacking the large gem quality crystals, richer in magnesium. So the clear, green peridots have lain safely for millions of years, cradled in their rock womb, whose relative plasticity has shielded them from seismic blows of fate, until men discovered them and hoisted them from the darkness of their dens into the golden sunlight. Mining in the soft serpentine is comparatively easy and it is sufficient to blast quarries out of the mountain flank or to sink shafts. The rock fragments are then reduced with stone hammers and the peridot crystals, which may weigh up to100 carats, are thus released and collected up into baskets by hand.

A decidedly unique source of “precious olivine” was discovered in the year i 749 in the east Siberian province of Yenisei. Perfect cuttable crystals were found in a large meteorite, named the Krasnoyarsk Meteorite after the provincial capital. This was the more remarkable because, while other gemstones also do literally fall from the heavens, though they are always tiny, peridot is not even common on earth. Shortly after the Second World War its distribution shrank even more. A gemstone variety closely related to it, and for a long time regarded as peridot, was proved to be a mineral in its own right. Because of its sole occurrence in Ceylon, it was named sinhalite in reference to the old Sinhalese name of its home, Sinhala.

The delightful appearance of peridot and its piquant attraction dubbed it the premier gemstone of the Baroque era, and made its green the hallmark of the age; for its lovely color admirably suited the mentality and decorative schemes of that stylistic epoch. The golden olive green, with its slightly oily glaze, was and is a favorite of gracious beauty and glittering luster. A peridot of 192 carats’ weight, crystal clear and of an exquisite olive green, is believed to have been formerly part of the Russian Czarist insignia. Because of its summer-fresh green, peridot is regarded as the birthstone for the month of August. Mounted in gold and worn on the left hand, it is said to put ghosts and demons to flight, dispel melancholy and foolishness, and to show the eternal paths to wisdom.

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