(1) Opal necklace. The hardness of opal is low, so friction with other objects should be avoided. Opal contains water, so it should be protected from high temperature. Otherwise, if the water is lost due to evaporation, the transparency will be lost, and if the water is lost, it will explode. In addition, Opal is not acid resistant, so high temperature and acidic substances should be avoided when wearing Opal jewelry. When collecting opal jewelry, it should also be noted that the environment should not be too dry, otherwise it will also cause dehydration and cracks, or even cracks. In order to prevent dehydration, opal jewelry should be soaked in clean water once every certain time in the dry season.

(2) Amethyst necklace. The color of amethyst is unstable and will fade in case of high temperature or prolonged exposure. Avoid high temperature or exposure to sunlight during wearing or storage.

(3) Lapis lazuli necklace. After the lapis lazuli necklace is stained, it must not be soaked and washed with water. Because lapis lazuli is a granular aggregate composed of a variety of minerals, if soaked and washed with water, the dirt on the surface of the gem will penetrate into the interior, so that the original luster of lapis lazuli will be changed. After the lapis lazuli jewelry is stained, gently wipe it with a damp cloth to remove the dirt.

(4) Jade necklace. Although the jadeite is hard and tough, it has a certain impact resistance. However, the processed jadeite products are often thin and will be damaged by impact.

(5) Malachite and turquoise necklaces. The hardness of these two gemstones is higher than that of water, and they are very easy to wear. The chemical properties of the two are unstable and will be corroded and dissolved in acid. Turquoise is easy to change color under high temperature, even if it is exposed to sunlight and soaked in sweat for a long time, turquoise will also change color. These must be paid attention to during wearing and collection.

(6) Emerald necklace. Emerald is slightly harder than jadeite, but it is more brittle than jadeite, so it can not withstand impact and beating. In addition, emerald is afraid of high temperature, and its color will fade in case of fire, so it is easy to crack under high temperature.

(7) Pearl and coral necklaces. The hardness of pearls and corals is very low, and the surface is easy to lose luster due to friction. Both are calcium carbonate, which will be corroded and dissolved in case of acid. It is easy to sweat in summer, and sweat will also damage the surface of pearls and corals and lose their original luster. Powders, perfume and hair creams in cosmetics will also gradually fade pearls. Therefore, it is better not to wear such jewelry in summer. If it is stained by sweat, it can be rinsed in clean water and then lightly wiped with soft fabric. Pearl jewelry must be rinsed with clean water before collection, and the storage place must also avoid cosmetics.