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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.


  • There are 28 Opal gemstones available at Multicolour.com
  • Opal(s) are organized in the following categories: CloseoutSingle,  gemstones.
  • Our most expensive Opal is USD 1402.20 and largest Opal weight is CTS 58.36.
  • Our cheapest Opal is USD 36.00 and smallest Opal weight is CTS 3.69.

Find your Opal

Our Opal(s) are available in various shapes, sizes and colors. 28 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/
Tanzanite Single
From our finest gemstones collection
Tanzanite Single Oval Eye clean
Size: 15.40 X 10.50 MM
Weight: 10.140 CTS
Shape: Oval
Clarity: Eye clean
Usually ships within 24 hours
OUR PRICE
USD 3853.20
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Deal of the Day/
Turquoise Single
limited time offer, ref# XTQ107aq
Turquoise Single Fancy Opaque
Size: 48.71 X 23.24 MM
Weight: 45.490 CTS
Shape: Fancy
Clarity: Opaque
Usually ships within 24 hours
10 % OFF, YOU SAVE 9.10 USD
NOW ONLY
USD 81.88
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Today’s Trade/
Best Selling Gems:
Sapphire Sapphire
1606 Sapphire ’s available
Browse gems | Learn More
Spinel Spinel
399 Spinel ’s available
Browse gems | Learn More
Alexandrite Alexandrite
273 Alexandrite ’s available
Browse gems | Learn More
Tanzanite Tanzanite
460 Tanzanite ’s available
Browse gems | Learn More
Zircon Zircon
237 Zircon ’s available
Browse gems | Learn More
Gemstone Variety: Hits Index
Going Up Amber +2851 +0.1%
average price USD 179.62 per item
Going Up Sapphire +1985 +0.1%
average price USD 385.88 per item
Going Down Alexandrite -636 -0.1%
average price USD 2000.98 per item
Going Up Anatase +1063 +0.3%
average price USD 206.25 per item
Going Up Turquoise +53 +0.0%
average price USD 55.56 per item
See more real time gem reports.
Exchange rates to USD
Canada Dollars 1.369
Euro 0.936
United Kingdom Pounds 0.791
Japan Yen 158.888
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Gem Library /
Gems Legend and  Lore This month birthstone: Alexandrite, Pearl
More from the Gem Library about Birthstones.
Cancer Cancer
June 21 – July 22
Cardinal Sign. Relates to water. Your zodiac stone...more

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