Ruby Many rubies are heat-treated to improve their color and clarity. Sometimes small surface flaws are also filled in to improve the stone's appearance, but this is only detectable by a trained gemologist. High heat or chemicals can damage treated rubies. Store rubies carefully to avoid damaging your other jewelry. Clean with warm soapy water or an ultrasonic cleaner.
Sapphires are very hard stones, so store carefully to avoid scratching other jewelry.
Clean with warm soapy water or an ultrasonic cleaner. This type of gemstone is often heated to lighten its color, or irradiated to deepen its color. While durable, smoky quartz can lose its color from exposure to high heat, and sudden or extreme temperature changes can cause it to fracture. Clean with warm soapy water or an ultrasonic cleaner, but avoid steam cleaning. Tanzanite This type of gemstone is often heat-treated to produce a range of colors.