Sapphires were believed to attract divine favor to their owners- Diamonds, Gems

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Evaluating Gem Diamonds

A gem can be called ruby only if it is a corundum of a red or purple-red hue and medium to dark in shade. A pink or light-red corundum would more properly be called a pink sapphire. The finest rubies known come from Burma, although Burma also produces stones of lesser quality.

The finest red-colored Burmese gems have been called "pigeon's-blood," and the most important producing area in Burma centers around the city of Mogok. Rubies have been mined here for more than 700 years. The geology is distinguished by the presence of very old metamorphic rocks and large bodies of marble, both of which are cut by pegmatite dikes.

This has given rise to a huge variety of minerals, and no other locality in the world produces as great a wealth of gem minerals. Most rubies on the market today come from other localities, however, and are not as fine as Burmese gems.

DIAMONDS, GEMSTONES & CRYSTALS
FACTS & FIGURES

The gem minerals were eroded from their parent rocks in ancient 50 geologic time periods, and then concentrated by streams in beds ofgravel. Over the centuries the gravel beds became buried by soil to a depth of as much as 15 feet. Mining of the gem gravels involves removal of this overburden, or tunneling into it from a vertical shaft dug by hand. All the gems are mined by primitive hand methods, involving wire baskets in which the gravels are washed and sifted, and several stages of sorting.

Sri Lanka (Ceylon) also produces ruby and sapphire, especially in 52 the area around Ratnapura, which in Singhalese means "city of gems."Mining methods here are similar to those in Burma, and the occurrence of gemstones is also in lenses or pockets of gravel buried at some depth. Ceylon ruby tends to be paler than material from Burma, but Ceylon sapphires are among the world's finest. Ceylonese sapphires in shades of pale blue, violet, deep blue, yellow, white, green, greenish-blue, brown, and pink are known, as well as a distinctive pinkish-orange shade known as "padparadsha".

Rubies from Thailand (Siam) tend to be dark purple-red or brownish-red, resembling garnets, although some pink stones are also round. Thai sapphires, especially greenish-yellow and grayish-blue stones, are of fair quality; the most notable locality is the Chant bun area, and a place called Battambang, which is now within the borders of Cambodia. Cambodia today is an important source of fine sapphires, especially the locality known as Pail in. Many fine black star sapphires come from Cambodia also.

Some of the world's most famous sapphires come from India, in the Vale of Kashmir high in the Himalayas. The fine blue gems found here have been known for about 100 years, but because of the high elevation mining can be carried out only a few months of the year.

India also produces ruby and star ruby, though of poor quality. The Indian sources are very ancient, and some were known at the time of Marco Polo.


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