for the necklace,different gemstone jewelry has different characteristics.thus ,there are some special requirment and precautions are respectively introduced as follows:
amethyst necklace :for the color of amethyst is not stable ,the high temperature or prolonged exposure will cause fading. thus ,during the Wearing  or the collection process, should avoid high temperature or exposure.

Malachite and turquoise necklace: Hardness of the two stones is small, it is very easy to be abrased .at the same time ,due to instable chemical nature,
 the two will be subject to corrosion in the event of dissolution of acid.

especialy the turquoise is extreamlly to fade at high temperatures, and longer exposure, these must be paid attentionare in the process of wear and collectors .

Pearl and coral necklace. Low hardness of pearls and coral, easily lose their luster due to the surface friction.
Both ingredients are calcium carbonate, the event will be subjected to corrosion of acid dissolution.

Easy sweat summer, sweat and also make pearls and coral lose the surface of the original luster.
The powder cosmetics, perfume and hair cream, also makes pearls gradually degenerate.

Therefore, the summer's best not to wear such jewelry.
If, after perspiration stain may be placed in clean water for rinsing, and then soft fabric can be gently wiped away.
Pearl jewelry in the collection before, be sure to clean water after rinsing, the place where collect the pearl must also be kept away from cosmetics.