Opal is an amorphous form of silica, chemically similar to quartz, but containing 3% to 21% water within its mineral structure. Gem grade opals usually have 6% to 10% water content. Opal is a sedimentary stone.
Is opal a crystal or a gem?
Unlike most other gemstones, opal is therefore not a crystal, but rather an amorphous solid. Opal is found in fossilized shell, wood and bone. Some precious opal forms in gas cavities in volcanic rocks, as in Mexico, and Slovakia, but most Australian deposits occur in sedimentary rocks.
What is an opal classified as?
Opal is a hydrated amorphous form of silica (SiO. nH2O); its water content may range from 3 to 21% by weight, but is usually between 6 and 10%. Because of its amorphous character, it is classed as a mineraloid, unlike crystalline forms of silica, which are classed as minerals.
Is a opal a diamond?
Opals, unlike diamonds, are genuinely rare – as fast as opals are mined, they are sold. … Unlike diamonds however (which are incredibly hard), opals are a relatively soft gemstone. Opals rank at about 5 or 6 on Mohs scale of mineral hardness, whereas diamonds rank at 10.
What is the difference between opal and gemstone?
Common opals often look similar to other stones like jasper. However, common opal is significantly less durable than most gemstones, ranking at a 5.5-6 on the Mohs scale of mineral hardness. That means you can scratch this gem’s surface with a basic pocket knife. Another identification method is by weight.
Is opal a birthstone?
Opal, the primary October birthstone
The October birthstone is the opal … or possibly tourmaline, depending on your source. Opals are the most well known birthstone for October.
Is opal natural stone?
The very first thing you should know is that the gemstone Opal is natural — It’s formed from a solution of silicon dioxide and water. Essentially, this precious gemstone is formed when water runs down the earth and seeps down into crevasses in the rock.
What are 3 different types of opals?
There are many different types of natural opals. There is black opal, white opal, crystal opal and jelly opal. There are other kinds – fire opal, hyalite, water opal, hydrophane and honey opal. Black Opal is the most valued of Opals and comes mainly from Lightning Ridge.
What are fire opals?
Fire Opal is an amorphous mineraloid comprising an accumulation of tiny hydrated silica spheres that produce a dominant reddish-orange spectrum upon light reflection. Although it is commonly misclassified as a “mineral,” fire opal is actually not a mineral because it does not have its own crystalline structure.
How do I identify an opal?
Look at the side of the opal – if it has distinct visible ‘layers’, it may be a doublet or triplet (i.e. not a solid opal) In this case, one of the layers will be a thin slice of opal, attached to the dark backing. A triplet will have a third layer, which is a clear, domed layer on top of the opal.
Is opal a soft gem?
Opals are in the range 5.5 – 6.5 on the Mohs hardness scale. That’s a relatively soft gem, meaning there are a number of substances that can scratch it. For example, small particles of quartz are common in household dust, and quartz is a 7 on the Mohs scale.
Is opal worth more than diamond?
Getting your hands on opal is easy, but finding gem-quality opal is another story. Diamonds, on the other hand, fetch a high price even for the most low-quality diamonds. … Because the value of most diamonds will be higher than opals, while high-quality opals are rarer than diamonds.
Is opal a hard or soft stone?
Solid Opals – Opal is a soft stone, approximately the same hardness as glass (around 6.5 on Moh’s hardness scale), so it is important to treat your opal carefully in order to avoid damaging it. … Many people believe solid opals can be damaged by water – however, this only applies to doublets and triplets.
What is the rarest opal color?
Black opal is the most rare and highly valued form of opal, and has what is called a black (or dark) body tone. Black opals come in every colour of the rainbow.
What is a raw opal?
These are all natural precious opal gemstones in their original state, without any treatments. These are strong, stable opals that won’t easily fall apart or crumble as you can cut, sand, polish, and carve them into the shape you need for your own custom opal jewelry creation.
What does opal Crystal do?
Opal is an emotional stone and reflects the mood of the wearer. … Opal enhances cosmic consciousness and induces psychic and mystical visions. It stimulates originality and creativity. Helps to release anger and claim self worth, aiding in accessing and expressing one’s true self.