安裝中文字典英文字典辭典工具!
安裝中文字典英文字典辭典工具!
|
- Opal - Wikipedia
Main opal producing countries Opal is a hydrated amorphous form of silica (SiO 2 ·nH 2 O); its water content may range from 3% to 21% by weight, but is usually between 6% and 10%
- Pictures of Opal - Black, Fire, Boulder, Blue and Pink
Physical Properties of Opal Although opal has a composition that includes SiO 2, its physical properties are very different from quartz Opal also has water, which reduces its specific gravity, gives it a lower hardness, and makes it much more brittle
- Types of Opals: A Comprehensive List of Opal Types, Origins . . .
Learn about all the different opal types and meanings in this comprehensive guide, plus how to classify them by color, inclusions, formation, origin, and more!
- Opale - Wikipedia
L'opale (simbolo IMA: Opl [3]) è un minerale colloidale amorfo, costituito da silice idrata (SiO 2 ·nH 2 O), semiamorfo o microcristallino, ovvero privo di struttura reticolare, infatti non si presenta in cristalli, ma in vene, noduli e croste di vari colori, spesso con iridescenze [4]
- Opal Description - GIA
"The Path of Enlightenment" necklace contains 180 magnificent opals from Lightning Ridge, Australia, a famous opal producing area - Courtesy Cody Opal Opal is the product of seasonal rains that drenched dry ground in regions such as Australia’s semi-desert “outback ” The showers soaked deep
- Opal: Mineral information, data and localities. - mindat. org
Although it is still (2007) regarded as a mineral species for historical reasons, opal is not a true mineral in the accepted sense of the word as it is variably composed of poorly crystalline material related to cristobalite and or tridymite and or composed of X-Ray amorphous silica
- OPALE - definition of OPALE by The Free Dictionary
Define OPALE OPALE synonyms, OPALE pronunciation, OPALE translation, English dictionary definition of OPALE ) n 1 A mineral of hydrated silica 2 A gemstone made of this mineral, noted for its rich iridescence o′pal·ine′ ) adj American Heritage® Dictionary of
- Opal - International Colored Gemstone Association
The ancient naturalist known as Pliny the Elder, during the first century A D , described opal as containing the glories of the most precious gems—the gentle fire of ruby, the rich purple of amethyst, the deep blue of sapphire, and the sea-green of emerald, all shining together in an indescribable union
|
|
|