Avoid Heat or pressure. Acids, strong solvents,and chemicals can cause damage. Do not use ultrasonic cleaners.

Avoid heat and solvents. Acids can cause damage. Do not boil or use ultrasonic cleaning.

Liquid inclusions may burst upon heating. Do not boil. Ultrasonic cleaning is safe.

Avoid all solvents and acids. Opals are highly sensitive to heat. Do not boil or use ultrasonic cleaning.

Exposure to heat can cause color loss or change. Some pink apatite may fade in light. Sulphuric and hydrochloride acid can cause damage. Do not boil or use ultrasonic cleaning.

Pearls are attacked by acids. Avoid any type of solvent or acid. Including perfume, hair spray and perspiration. Do not boil or use ultrasonic cleaning.

Liquid inclusions may burst upon heating. Hydrofluoric acid may cause damage. To be safe, do not boil; use ultrasonic cleaning.

As a general rule, treat with extreme care. Do not boil or use ultrasonic cleaning. Note, however, that ultrasonic cleaning may be safe with some current enhancement methods. Know what you are dealing with or us only warm, soapy water.

Uneven or sudden heat may result in fracturing or complete breakage, Hydrocloric acid can cause damage; sulphuric acid can easily cause damage. Do not boil and use caution with ultrasonic cleaning.

Strong heat may turn these gems colorless. Abrupt temperature changes may cause fractures. The stones are soluble in hydroflouric acide and ammonium flouride and very slightly soluble in alkalis. Boiling is generally safe, but use caution with ultrasonic cleaning.

Stable when exposed to heat, light, and chemicals. However, since high value is involved, use caution and avoid boiling and ultrasonic cleaners when possible.

Light gems may fade under intense heat. Boiling is generally safe. Use caution with ultrasonic cleaning.

Generally safe to boil and use ultrasonic cleaning. With stones of high value, some caution may be prudent.

Very sensitive to heat and strong light, very slowly attacked by concentrated hydroflouric acide. Do not boil or use ultrasonic cleaning.

Generally safe to boil and use ultrasonic cleaning unless fracture-filled.

Avoid thermal shock. Although boiling us possible, it is not recommended, since thermal shock can cause damage. Because of poor toughness also use caution with ultrasonic cleaning.

Highly sensitive to heat. Hydrofluoric acid can cause damage. Do not boil or use ultrasonic cleaning.

Sudden temperature changes may cause fracturing. Although boiling is possible, it is not recommended, since thermal shock can cause damage.

Concentrated hydrofluoric acid may cause may cause damage. Abrupt temperature changes likely to cause fractures. Pyrope melts easily under the jeweler's torch. Generally safe to boil, but avoid thermal shock. Use care with ultrasonic cleaning.

Avoid strong solvents. Highly heat-sensitive; dissolves slowly in hydrochloric acid. Specific gravity liquids (used by gemologists in the identification process), perspiration, and cosmetics may discolor surface. Do not boil or use ultrasonic cleaning.

Acids can cause damage. Relatively safe to boil and use ultrasonic cleaning, however be aware of existing cleavages.

Gems abrade easily. Heat may alter color; some gems may revert to original color when exposed to light. Avoid boiling, but ultrasonic cleaning is safe.

Avoid strong solvents, acids, high heat, and strong sunlight. Jadeite is very tough and generally will withstand boiling and ultrasonic cleaning. Be aware that wax coated jade could be affected.

Sudden temperature change may cause fracturing. Hydrochloric and hydrofluoric acid can cause damage. Do not boil or use ultrasonic cleaning.

Hydrochloric acid can cause damage. Cyanide solution causes reddish-brown discoloration. Keep dyed strands away from heat, solvents, or harsh detergents. Do not boil or use ultrasonic cleaning.