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Ammolite is an opal-like organic gemstone found primarily along the eastern slopes of the Rocky Mountains of North America.It is commonly unearthed by natural erosion or through the process of various mining practices, within the perimeter of an ancient sea bed called the Western Interior Seaway. [2]
A Peruvian opal (also called blue opal) is a semi-opaque to opaque blue-green stone found in Peru, which is often cut to include the matrix in the more opaque stones. It does not display a play of color. Blue opal also comes from Oregon and Idaho in the Owyhee region, as well as from Nevada around the Virgin Valley. [17] Opal is also formed by ...
Malachite is a copper carbonate hydroxide mineral, with the formula Cu 2 CO 3 (OH) 2.This opaque, green-banded mineral crystallizes in the monoclinic crystal system, and most often forms botryoidal, fibrous, or stalagmitic masses, in fractures and deep, underground spaces, where the water table and hydrothermal fluids provide the means for chemical precipitation.
Spectrolite exhibits a richer range of colors than other labradorites as for instance in Canada or Madagascar (which show mostly tones of blue-grey-green) and high labradorescence. [ 1 ] [ 2 ] Due to the unique colors mined in Finland , spectrolite has become a brand name for material mined only there.
Hyalite is a transparent form of opal with a glassy lustre. It may exhibit an internal play of colors if natural inclusions are present. It is also called Muller's glass, water opal, and jalite. Müller's glass is named after its discoverer, Franz-Joseph Müller von Reichenstein.
[4] In contrast, common opal does not display an iridescence, but often exhibits a hazy sheen of light from within the stone – the phenomenon that gemologists strictly term as opalescence. [5] This milky sheen displayed by opal is a form of adularescence. [6]
[3] [4] It occurs most often in granite pegmatite [3] [4] [5] and allied rock types and in certain low-grade metamorphic phyllites. Sources include Australia, Myanmar , India, Afghanistan, Israel, Madagascar , Namibia , Nigeria , Mozambique , Tanzania and the United States. [ 2 ]
100 Greatest is a long-running TV strand on Channel 4 in the United Kingdom that has been broadcasting from 11 September 1999 to 10 October 2015, originating in Tyne Tees Television’s Factual Features department under Executive Producer Mark Robinson. The "list show" programmes are generally public polls, and reflect the votes of visitors to ...