- Opal - Wikipedia
The internal structure of precious opal causes it to diffract light, resulting in play-of-color Depending on the conditions in which it formed, opal may be transparent, translucent, or opaque, and the background color may be white, black, or nearly any color of the visual spectrum
- 14 Different Types Of Opal And What They All Look Like
Explore the vibrant world of gemstones! Learn about the different types of opal and where to find them in our comprehensive guide
- Pictures of Opal - Black, Fire, Boulder, Blue and Pink
Photos of opal from around the world Guidance for people who want to buy opal, see different types of opal, understand their names, learn about synthetics and imitations
- Opal - Gemological Institute of America
An opal might show a single color, two or three colors, or all the colors of the rainbow! The best play-of-color is the brightest; if it also has all the rainbow colors, then it is very rare and valuable
- Opal | Properties, Types Uses | Britannica
Opal, silica mineral extensively used as a gemstone, a submicrocrystalline variety of cristobalite In ancient times opal was included among the noble gems and was ranked second only to emerald by the Romans
- Opal - International Colored Gemstone Association
October’s birthstone, opal is a gem of positive transformation, revealing the colorful attributes of those who wear it Magical, mysterious, and lively—opal is captivating new admirers with its variety
- What Is Opal: Everything You Need to Know - Nobbier
What Is Opal? Opal is a hydrated amorphous form of silica (SiO₂·nH₂O) containing between 3-21% water within its mineral structure Unlike crystalline gemstones that have orderly, repeating atomic structures, opals form from silica-rich solutions that flow into cracks and cavities in rock
- Opal History and Lore - GIA
Opal is considered an October birthstone Some people think it’s unlucky for anyone born in another month to wear an opal But that particular superstition comes from a novel written in the 1800s (Anne of Geierstein by Sir Walter Scott), and not from any ancient belief or experience
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