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Natural Opal

Opal is a poorly crystalline or amorphous hydrous silica that is compact and vitreous and most commonly translucent white to colourless. Precious opal reflects light with a play of brilliant colours across the visible spectrum, red being the most valued. Opal forms by precipitation from silica-bearing solutions near the Earth's surface. Electron microscopy has shown that many opals are composed of spheres of tens to a few thousand angstroms in size that are arranged in either hexagonal or cubic close packing. The spheres are composed of hydrous silica that may be either almost cristobalite-like, tridymite-like, mixtures of both, or random and nondiffracting. The specific gravity and refractive index are lower than those of pure silica minerals. The play of colours in precious opal arises from the diffraction of light from submicroscopic layers of regularly oriented silica spheres. When heated, opal may lose as much as 20 percent of its weight of water, fracture, and then crystallize to one of the silica minerals described above.


Find your Opal

Our Opal(s) are available in various shapes, sizes and colors. 92 Opal(s), too many to look through? You may select any combination of search options. Colors grade into each other and you can search for more than one color at once. For a better selection, try selecting two or three colors, -- your first choice plus the two closest colors.

Shape Length (mm) Width (mm)
Category Weight (cts) Price (USD)
Color range
orangy yellow
yellow

Opal Profile

Color information: White, green, blue, black, red, orange, violet, pink, grey, yellow.
Refractive Index: 1.44-1.46
Chemical Composition: SIO2nH2O
Hardness: 5.5 - 6.0
Density: 2.65 - 3.00
Crystal Group: Amorphous
Ocurrence: Czechoslovakia, Mexico, Honduras, Australia, Brazil, Tanzania.
Sign of the Zodiac: N/A
Month of the year: N/A
Opal
Opal usually contains 4 to 9 percent water, but lower and much higher values have been observed. The contents of alumina, ferric oxide, and alkalis are variable but may amount to several percent in light-coloured opals and more if pigmenting minerals are also present. Precious opal has been synthesized. Opaline silica is a friable hydrous silica found near hot springs and geysers.

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Finest gems/
Alexandrite Single
From our finest gemstones collection
Alexandrite Single Trillion Eye clean
Size: 11.40 X 7.80 MM
Weight: 3.380 CTS
Shape: Trillion
Clarity: Eye clean
Usually ships within 24 hours
OUR PRICE
USD 14250.00
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Deal of the Day/
Alexandrite Single
limited time offer, ref# YAX812ab
Alexandrite Single Marquise Moderately to Heavily included
Size: 4.60 X 2.20 MM
Weight: 0.180 CTS
Shape: Marquise
Clarity: Moderately to Heavily included
Usually ships within 24 hours
10 % OFF, YOU SAVE 12.60 USD
NOW ONLY
USD 113.40
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Today’s Trade/
Best Selling Gems:
Sapphire Sapphire
803 Sapphire ’s available
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Spinel Spinel
368 Spinel ’s available
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Tanzanite Tanzanite
268 Tanzanite ’s available
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Alexandrite Alexandrite
222 Alexandrite ’s available
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Zircon Zircon
263 Zircon ’s available
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Gemstone Variety: Hits Index
Going Up Sapphire +3661 +0.2%
average price USD 331.86 per item
Going Up Alexandrite +3413 +0.2%
average price USD 2681.19 per item
Going Up Tsavorite +1339 +0.1%
average price USD 265.41 per item
Going Up Diamond +150 +0.0%
average price USD 9247.44 per item
Going Up Spinel +289 +0.0%
average price USD 558.06 per item
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Gem Library /
Gems Legend and  Lore This month birthstone: Alexandrite, Pearl
More from the Gem Library about Birthstones.
Gemini Gemini
May 21 – June 20
Dual nature. You can go in many directions. Your zodiac stone...more

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