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Gem Care
 Care and Durability Factors by The Gem Reference Guide, Published by the Gemological Institute of America.
JANUARY – Garnet - Hardness: 7 to 7 ½
Cleaning Methods:
- Ultrasonic: usually safe
- Steamer: never
- Warm soapy water: safe
Stability:
- Reaction to Heat: abrupt temperature changes likely to cause fracturing
- Stability to Light: stable
- Reaction to Chemicals: virtually none, very slightly attacked by concentrated hydrofluoric acid.
FEBRUARY - Amethyst – Hardness: 7
Cleaning Methods:
- Ultrasonic: usually safe
- Steamer: risky
- Warm soapy water: safe
Stability:
- Reaction to Heat: strong heat turns stone colorless, or may produce a citrine or green color; however, gentle heating may lighten the color. Abrupt temperature change may fracture stone.
- Stability to light: some stones may fade
- Reaction to Chemicals: soluble in hydrofluoric acid and ammonium floride; very slightly soluble in alkalies.
MARCH – Aquamarine – Hardness: 7 ½ to 8
Cleaning Methods:
- Ultrasonic: usually saf, unless stone contains feathers or liquid inclusions
- Steamer: usually safe, unless stone contains feathers or liquid inclusions
- Warm soapy water: safe
Stability:
- Reaction to Heat: generally not heat sensitive unless contains liquid inclusions
- Stability to light: stable
- Reaction to Chemicals: attacked by hydrofluoric acid
APRIL – Diamond – Hardness - 10
Cleaning Methods:
- Ultrasonic: usually safe, unless contains feathers
- Steamer: usually safe, unless contains feathers
- Warm soapy water: safe
Stability:
- Reaction to Heat: begins to vaporize in oxygen-rich atmosphere at 690 C to 875 C
- Stability to light: stable
- Reaction to Chemicals: none
MAY – Emerald – Hardness – 7 ½ to 8
Cleaning Methods:
- Ultrasonic: never
- Steamer: never
- Warm soapy water: generally safe, but avoid strong detergents and vigorous scrubbing on oiled stones
Stability:
- Reaction to Heat: may cause additional fracturing or compete breakage
- Stability to light: stable, except possible fading in stones treated with green oil
- Reaction to Chemicals: resistant to all acids except hydrofluoric; solvents may drive out oil
JUNE – Pearl – Hardness – 2 ½ to 4
Cleaning Methods:
- Ultrasonic: never
- Steamer: never
- Wipe with very soft cloth after each wearing
- Warm soapy water: safe for more thorough cleaning (if strung, be sure string is completely dry before wearing)
Stability:
- Reaction to Heat: excessive heat, such as open flame, may cause pearls to burn, turn brown, split, or crack.
- Stability to light: stable
- Reaction to Chemicals: attacked by all acids; acid perspiration, perfume, or hairspray also attacks nacre
JULY – Ruby – Hardness - 9
Cleaning Methods:
- Ultrasonic: usually safe, but never for oiled stones
- Steamer: usually safe, but never for oiled stones
- Warm soapy water: safe, but avoid strong detergents and vigorous scrubbing on oiled stones
Stability:
- Reaction to Heat: sometimes improves color
- Stability to light: stable
- Reaction to Chemicals: attacked with difficulty
AUGUST – Peridot – Hardness – 6 ½ to 7
Cleaning Methods:
- Ultrasonic: risky
- Steamer: never
- Warm soapy water: safe
Stability:
- Reaction to Heat: uneven or rapid heat may cause fracturing or complete breakage
- Stability to light: stable
- Reaction to Chemicals: Acid perspiration of some people may attack over a long period of time.
SEPTEMBER – Sapphire – Hardness - 9
Cleaning Methods:
- Ultrasonic: usually safe
- Steamer: usually safe
- Warm soapy water: safe
Stability:
- Reaction to Heat: sometimes improves color, but may cause loss of color
- Stability to light: stable, except for irradiated yellow and orange sapphires
- Reaction to Chemicals: attacked with difficulty
COTOBER – Opal – Hardness – 5 to 6 ½
Cleaning Methods:
- Ultrasonic: never
- Steamer: never
- Warm soapy water: safe
Stability:
- Reaction to Heat: sudden changes in temperature may cause opals to crack, craze, or fracture;
overheating will turn most opals white or brownish, and play-of-color will disappear
- Stability to light: stable
- Reaction to Chemicals: attacked by hydrofluoric acid and caustic alkalies
NOVEMBER – Topaz – Hardness – 8
Cleaning Methods:
- Ultrasonic: never
- Steamer: never
- Warm soapy water: safe
Stability:
- Reaction to Heat: rapid heating or cooling will cause internal breaks; strong heat may
alter or destroy color
- Stability to light: some brown stones fade
- Reaction to Chemicals: affected very slightly
DECEMBER – Tanzanite – Hardness – 6 to 7
Cleaning Methods:
- Ultrasonic: never
- Steamer: never
- Warm soapy water: safe
Stability:
- Reaction to Heat: fuses under jewelers torch; sudden temperature changes (heating or cooling) may cause cracking
- Stability to light: stable
- Reaction to Chemicals: attacked by hydrochloric and hydrofluoric acid
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