- Brand: Casa de plata
- Product Code: STN-50
- Availability: By Order
It is recognized as the official birthstone for the month of February. Amethyst belongs to the microcrystalline branch of quartz and owes its violet/purple color to iron and aluminium impurities. Without such colouring agents, amethyst would simply be transparent, ordinary colourless quartz. Like other varieties of microcrystalline quartz, amethyst has transparent to translucent clarity and a vitreous luster. Cryptocrystalline varieties of quartz almost always occur with translucent to opaque clarity.
Opal is famed for its ability to diffract light. The exact cause of opal's unique properties was only recently discovered by Australian scientists in the 1960s after analysis with electron microscopes. It was discovered that small spheres of silica gel caused interference, refraction and diffraction of light, resulting in opal's distinctive play of color. The varying refractive indices of the spheres and spaces between them dissect the light on its passage through the stone. As light enters the opal, it bends around the tiny particles or 'spheres' of hydrated silica, as well as 'chips' of silicon and oxygen suspended within the stone. Light is comprised of all visible colors and can produce an entire spectrum of colors when it is diffracted.