February Birthstone: Amethyst

• Amethyst comes in purple to pastel shades. GIA calls strong reddish purple to purple, with no visible color zoning, the finest color.
• Most amethyst has no inclusions you can see, so look for even color first.

• Heat is the most common treatment. It cannot make pale amethyst darker, but it can lighten a very dark stone, and the change is permanent. Some amethyst turns yellow when heated and becomes citrine.
• Lab-grown amethyst has been made since the 1970s. It has the same chemical and physical properties as natural amethyst. Without advanced testing it can be very hard to tell apart, so sellers are required to tell you whether a gem is natural or synthetic.

At 7 on the Mohs scale, amethyst is fine for rings and other jewelry worn every day, though over the years it may show wear and need polishing again. Keep it away from rubies, sapphires and diamonds in a jewelry box, since they can scratch it.

• The name comes from the Greek for "a remedy against drunkenness", and early Greek myths linked the gem with Bacchus, the god of wine.
• Catherine the Great of Russia wore amethyst necklaces, earrings and other jewels.

• Warm, soapy water and a soft brush: always safe.
• Ultrasonic cleaner: usually safe.
• Steam cleaner: not recommended.

Some amethyst fades in strong light over time, and high heat can remove the color completely.