Hobbies And Interests
Composition
Rare gems have ordinary minerals as their components. A form of aluminum oxide called corundum serves as the chief component in rubies and sapphires. The basic emerald molecule contains beryllium, aluminum, silicon and oxygen. Both rubies and emeralds have chromium impurities, which makes rubies red and emeralds green. Some sapphires have lanthanum impurities.
Hardness
The Mohs scale measures the hardness of rare gems. The scale extends from one to 10 in order of hardness. Diamond, the hardest of substances, registers 10, while ruby and sapphire manage nine. Emerald is softer at seven and a half.
Effects of Light
Light tends to give rare gems a sparkling appearance. For example, a well-cut diamond will bend light sharply as it enters and reflect the light internally before it leaves, so that the diamond seems to be filled with light.
Cultural Significance
Besides their use in personal adornment, rare gems have a cultural and spiritual significance in many circles. For example, a Hindu sacred text called the "Bhavanopanished" calls man "an island of precious gems." People in India and China have traditionally attributed healing powers to gemstones; and modern astrology has followed suit, ascribing physical, mental and emotional well-being to various rare gems.