商品描述
▲▲▲ Black Silk Stone Geological PropertiesOnyx is a form of chalcedony, which is microcrystalline quartz formed in the gas cavities of lava. Its multi-layered structure is similar to that of agates. As with any onyx, black silk stone is found worldwide.Mineral Information: Oxide mineralChemical Composition: SiO2Color: Opaque-gray / blackHardness: 4 (Mohs)Specific Gravity: 2.70Refractive Index: 1.486 - 1.658▲▲▲ Customers can select a variation of closure.https://c1.staticflickr.com/1/953/41861913431_fb577e2724_z.jpg▲▲▲ Your item will come with our gift bag.https://live.staticflickr.com/65535/48641047828_8f0538660f_z_d.jpg▲▲▲ Shipping World Wide :- Please allow us to prepare the item and parcel between 1-5 working days.- All items will be sent by Thai Registered Airmail. The delivery usually takes about 10 - 15 working days for parcel to arrive in most countries.