无底价 - 克拉 60.0 顶级色彩 埃塞俄比亚欧泊 - 粗糙系列- 12 g

卓越的一批天然高贵的埃塞俄比亚毛坯欧泊，精选以品质和色彩戏剧性变幻为标准。
尺寸（长度方向）为7.0至15.0毫米。
所有图片都使用高分辨率相机，在完全干燥的材料上并在不同背景下拍摄，以尽可能真实地呈现欧泊的外观。
全球配送，使用挂号信并附带跟踪号码。
__________________________________________
An opal is a hydrated form of silica with a water content ranging from 3 to 21%.Indeed, it is this permeability to water that makes it a hydrophile.
Opals are deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl, and basalt. Only precious opals show a variable interplay of internal colors.
At microscopic scales, precious opal is composed of silica spheres some 150 to 300 nm in diameter in a hexagonal or cubic close-packed lattice. These ordered silica spheres produce the internal colors by causing the interference and diffraction of light passing through the microstructure of the opal.