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The black fire opal is the official gemstone of Nevada. Most of the precious opal is partial wood replacement. The precious opal is hosted and found in situ within a subsurface horizon or zone of bentonite, which is considered a "lode" deposit. Opals which have weathered out of the in situ deposits are alluvial and considered placer deposits.
The name opal is believed to be derived from the Sanskrit word upala , which means 'jewel', and later the Greek derivative opállios (ὀπάλλιος). There are two broad classes of opal: precious and common. Precious opal displays play-of-color (iridescence); common opal does not. Play-of-color is defined as "a pseudo chromatic optical ...
Biogenic silica (bSi), also referred to as opal, biogenic opal, or amorphous opaline silica, forms one of the most widespread biogenic minerals. For example, microscopic particles of silica called phytoliths can be found in grasses and other plants. Silica is an amorphous metalloid oxide formed by complex inorganic polymerization processes.
In fact, as it gets darker around the opal, the opal appears ever more vibrant. The stone's vivid and sparkly nature is in stark contrast to Coober Pedy, Australia where it was discovered.
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]
The Halley's Comet Opal is a very fine specimen, with few flaws or blemishes and a large green and orange 1.6 cm (0.63 in) thick color bar which goes through the opal. Formed about 20 million years ago, it is an example of a nobby, which is a natural lump-shaped opal found only at Lightning Ridge. [2] As of 2006 it was for sale at $1.2 million. [3]
Opals may have been around for thousands of years, but they’re having a major resurgence in the jewelry world right now. Chairish included opals as one of its top trend predictions for 2025, ...
Fiorite is a hydrated silica mineraloid, a form of opal, found in cavities in volcanic tuff. It is a globular, botryoidal, or stalactic concretionary form of opal. The mineraloid has a pearly lustre and forms botryoidal masses. Named after Santa Fiora, Italy, fiorite is used as a gemstone. [1]