0
If the basalt flow contains air bubbles and pockets and there is a spring that contains silica then the silica can deposit into the air bubbles (the air bubbles are known as Amygdaloidal basalt or vesicles) If the silica deposits slowly and the conditions are correct then precious opal can form. Two examples of this would be in California at the Nowak and the Barnett mines.
Still curious? Ask our experts.
Chat with our AI personalities
Judy
Fran
Blake
Add your answer:
Earn +20 pts
What is the chemical name for opal?
Opal is composed primarily of silica (silicon dioxide, SiO2) with varying amounts of water trapped within its structure.
Are there different kinds of opal?
Yes, there are different types of opal, including precious opal which displays flashes of iridescent color, common opal which lacks play-of-color, fire opal which displays vibrant orange, red, or yellow hues, and black opal which has a dark body tone with bright play-of-color. Each type has unique characteristics and qualities.
Is opal an intrusive or extrusive mineral?
Opal is not considered a rock but actually a mineraloid gel. It is deposited at relatively low temperatures. One of the characteristics if igneous rocks, sometimes called fire rocks, is that they are formed at high temperatures. Whether an igneous rock forms below ground, or on or near the surface, it's all about heat forming the rock. Opal cannot take its form under that kind of heat.
Are opals made from volcanoes?
Opals are not made from volcanoes. Opals are formed from a combination of silica-rich water and heat over long periods of time. They are typically found in the cracks and cavities of sedimentary rocks, not in volcanic environments.
What is another name for opal?
Another name for opal is "fire opal."
