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.
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- There are 28 Opal gemstones available at Multicolour.com
- Opal(s) are organized in the following categories:
Closeout, Single, 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.
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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.
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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 |
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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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Looking for other Gemstones?
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| Finest gems/ |
Emerald Single
From our finest gemstones collection
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| Size: |
8.06 X 9.28 MM |
| Weight: |
1.790 CTS |
| Shape: |
Heart |
| Clarity: |
Slightly to Moderately included |
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| Usually ships within 24 hours |
OUR PRICE
USD 19332.00
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| Deal of the Day/ |
Chrome Tourmaline Single
limited time offer, ref# YCH103aw
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| Size: |
7.60 X 6.00 MM |
| Weight: |
1.000 CTS |
| Shape: |
Fancy |
| Clarity: |
Slightly included |
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| Usually ships within 24 hours |
| 10 % OFF, YOU SAVE 13.50 USD |
NOW ONLY
USD 121.50
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| Today’s Trade/ |
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| Gemstone Variety: |
Hits |
Index |
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Amber |
+27358 |
+0.5% |
| average price USD 183.13 per item |
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Sapphire |
+11367 |
+0.4% |
| average price USD 398.26 per item |
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Parisite |
-2607 |
-0.3% |
| average price USD 122.67 per item |
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Alexandrite |
-10198 |
-1.3% |
| average price USD 2030.47 per item |
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Anatase |
-825 |
-0.1% |
| average price USD 221.50 per item |
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See more
real time gem reports. |
| Exchange rates to USD |
| Canada Dollars |
1.420 |
| Euro |
0.956 |
| United Kingdom Pounds |
0.791 |
| Japan Yen |
150.463 |
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our prices in your home currency. |
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