I held a bluish green emerald from Muzo, Columbia once and my heart skipped a beat. No other gem boasts a green quite like it. Lucky for you May babies, this is your birthstone.

Mineral Species: Beryl
Hardness: 7 1/2 to 8
Toughness: poor to good Color: Strongly bluish-green to green
Typically found in all sizes up to 4 carats. Faceted goods over 100 carats are also available.

Care:
Emerald is a brittle gem and often very included. Gentle wear and care is recommended for longevity.
Ultrasonic: Never
Steam: Never
Warm, soapy water: Generally safe. Avoid strong detergents and vigorous scrubbing on oiled stones.

Stability:
Heat: May cause additonal fracturing or complete breakage
Light: Stable, except in stones treated with colored oil.
Chemicals: Resistant to all acids except hydrofluoric acid. Solvents may damage or remove oil.

Common sources:
Columbia, Zambia, Brazil, Pakistan, Zimbabwe, Afghanista, Russia, Australia

Treatments:
Oiling is prevalent enough to be automatically assumed. This treament increases the apparent clarity of the stone and, in some cases, may imporve the color. This treatment is neither stable nor permanent. Avoid heat, solvents and ultrasonics.