无底价 - 92.10 克拉 顶级色彩 埃塞俄比亚欧泊 粗糙合集- 18.42 g

卓越的一批天然高贵的埃塞俄比亚粗糙欧泊，以质量和光彩变化效果为标准精选。
尺寸（长度方向）为 15 至 23 毫米。
所有照片均在干燥无水的材料上，使用高分辨率相机拍摄，并在不同背景下拍摄，以尽可能真实地呈现欧泊。
__________________________________________
全球包邮，使用挂号邮件并提供追踪号码。
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.