Dimensions: from 26 to 35 mm
High resolution pictures (on dry material) with macro magnification, without any improvement.
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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. Precious opals show a variable interplay of internal colours.
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 colours by causing the interference and diffraction of light passing through the microstructure of the opal.
- Forma mineral / Tipos de meteoritos
- Cts 141.0 Ópalos de Boulder australianos
- Ópalos australianos naturales
- 28.2 g
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