| Gemstone | Treatment Method(s) | Special Care Instructions |
Abalone | Sometimes dyed to improve color. | Abalone is easily scratched. Wear with care. Abalone is porous. Avoid contact with colored fluids. Avoid extended exposure to bright lights. Avoid contact with harsh chemicals, acids, solvents and heat. Do not expose them to ultrasonic cleaning. |
Amethyst | Occasionally heated to improve color. | Some untreated amethysts may fade in prolonged exposure to sunlight. |
Aquamarine | Usually heated to improve color. Occasionally fracture-filled to improve appearance. | Avoid contact with harsh chemicals and heat. Do not expose them to ultrasonic cleaning. |
Black Diamond | May be irradiated and/or heated to produce color. May be laser-drilled or fracture-filled to improve appearance. | Avoid recutting, steam cleaning and ultrasonic cleaning. |
Blue Topaz | Brown topaz stones are irradiated and often heated to produce blue topaz. | Avoid exposure to bright light. |
Brown Diamond | May be irradiated and/or heated to produce color. May be laser-drilled or fracture-filled to improve appearance. | Avoid recutting, steam cleaning and ultrasonic cleaning. |
Citrine | Citrine is produced by heating different varieties of quartz. | N/A |
Crystal | May be surface-coated to enhance color or appearance. | Avoid hard contact and abrasive surfaces. Keep away from cosmetics and household chemicals. |
CZ | May be surface-coated to enhance color or appearance. | Avoid hard contact and abrasive surfaces. Keep away from cosmetics and household chemicals. |
Diamond | Occasionally laser-drilled or fracture filled to improve appearance. On rare occasions, diamonds may be surface-coated or heated with pressure to alter their color and/or clarity. | Avoid recutting diamonds that have been fracture filled. For stones that have been surface-coated, avoid steam cleaning, ultrasonic cleaners, and alcohol. They may adversely affect the stones’ color and appearance. |
Drusy | May be surface-coated to enhance color or appearance. | Avoid recutting and repolishing. Avoid contact with abrasive surfaces. |
Emerald | Usually fracture filled with oil, wax or resin to improve appearance. Occasionally dyed to improve color. | Avoid sudden changes in temperature, ultrasonic cleaners, steam cleaners and chemicals. |
Garnet | Some varieties are heat-treated to improve color. | Avoid sudden changes in temperature. |
Jade | Often bleached or dyed to improve the stone’s color. Also commonly fracture filled with wax to improve the stone’s appearance. | Avoid heat, strong light, chemicals, and ultrasonic cleaners. |
Lemon Quartz | Usually heated to improve color. | N/A |
Marcasite | Not treated | Avoid acids and harsh chemicals. |
Moissanite | Most Moissanite is untreated. However, Moissanite can be surface-coated to change the stone’s color. | For surface-coated stones, avoid repolishing or recutting, steam cleaning, harsh chemicals and ultrasonic cleaners. |
Morganite | Commonly heat-treated or irradiated to improve color and appearance. | Avoid exposure to heat. |
Mother of Pearl | Sometimes dyed to improve color. | Mother of Pearl is easily scratched. Wear with care. Mother of Pearl is porous. Avoid contact with colored fluids. Avoid extended exposure to bright lights. Avoid contact with harsh chemicals, acids, solvents and heat. Do not expose them to ultrasonic cleaning. |
Mystic Topaz | Surface coated to change or improve color. | Avoid repolishing or recutting, steam cleaning, harsh chemicals and ultrasonic cleaners. |
Onyx | Dyed to improve color | Avoid prolonged exposure to bright light. |
Opal | Impregnated with colorless oil, wax, resin or plastic to improve appearance and durability. | Avoid heat, chemicals, heat and ultrasonic cleaners. |
Pearls | White pearls are bleached to improve color and uniformity. Colored pearls are often dyed, and occasionally undergo irradiation to improve their colors. | Avoid chemicals, cosmetics, and ultrasonic cleaners. |
Peridot | Sometimes fracture filled with colorless oil, wax or resin to improve appearance. | Avoid sudden changes in temperature, ultrasonic cleaners and harsh chemicals. |
Ruby | Usually heat-treated, and occasionally lattice-diffused to improve or change color. Commonly fracture-filled to improve appearance. On rare occasion, stones may be dyed or irradiated. | Avoid excess heat, harsh chemicals, prolonged exposure to light, and ultrasonic cleaners. Avoid repolishing or recutting when effect is near the surface. |
Sapphire | Usually heat-treated, and occasionally lattice-diffused to improve or change color. Sapphires are also occasionally irradiated to produce a temporary yellow or orange color. | Avoid excess heat, harsh chemicals, prolonged exposure to light, and ultrasonic cleaners. Avoid repolishing or recutting when effect is near the surface. |
Smoky Quartz | Commonly irradiated to enhance color. | Avoid exposure to bright light. |
Tanzanite | Heated to produce its violet-blue color. | Avoid sudden temperature changes and harsh abrasives. |
Tiger-eye | May undergo heat treatment or bleaching to improve color. | Avoid prolonged exposure to bright light. Avoid harsh chemicals and heat. Do not expose them to ultrasonic cleaning. |
Topaz | May undergo heat treatment, surface treatment, irradiation, or lattice diffusion to improve or change the stone’s color. | Avoid heat, exposure to bright light, repolishing or recutting, chemicals, and ultrasonic cleaners. |
Tourmaline | May be heated or irradiated to improve color. May be infused with colored oil, resin or dye to improve appearance. | Avoid sudden temperature changes, steam cleaning, and ultrasonic cleaning. |
Turquoise | Impregnated with colorless oil, wax, or plastic to improve appearance and durability. Sometimes dyed to improve color. | Avoid hot water and household chemicals. |
