Opal is a unique gemstone that has been prized for its beauty and rarity for centuries. However, there has been some controversy over whether or not opal should be considered a “real” stone, due to certain characteristics that set it apart from other gemstones. In this article, we will explore the properties of opal and examine why it is indeed a legitimate gemstone.
What is Opal?
Opal is a mineraloid, which means that it is a naturally occurring substance that does not have a crystalline structure like most minerals. Instead, opal is made up of tiny spheres of silica, which are arranged in a three-dimensional lattice pattern. This unique structure gives opal its characteristic iridescence, as light is diffracted and reflected by the spheres in different colors.
Types of Opal
There are several different types of opal, each with their own distinct characteristics. The most common types are:
- White Opal: This is the most common type of opal, and is characterized by its white or light-colored body color with flashes of color.
- Black Opal: Black opal is much rarer than white opal, and is characterized by its dark body color with flashes of color that are often more intense than those seen in white opals.
- Fire Opal: Fire opal is known for its bright orange or red body color, which is caused by the presence of iron oxide impurities.
- Boulder Opal: Boulder opal is found in ironstone boulders, and is characterized by its dark body color with veins of opal running through it.
Properties of Opal
Opal has several unique properties that set it apart from other gemstones. These include:
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Hardness
Opal is relatively soft compared to other gemstones, with a hardness rating of 5.5 to 6.5 on the Mohs scale. This means that it is more susceptible to scratches and damage than harder stones like diamonds or sapphires.
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Water Content
Opal contains varying amounts of water, which can range from a few percent to as much as 20%. This makes opal relatively fragile and prone to cracking if it dries out.
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Iridescence
As mentioned earlier, opal’s unique structure gives it its characteristic iridescence, which means that it displays different colors when viewed from different angles.
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Doublet and Triplet
Some opals are made into doublets or triplets, which consist of a thin layer of opal glued onto a backing material (doublets) or sandwiched between a top layer of quartz or glass and a backing material (triplets).
Is Opal a Real Stone?
Despite its unique properties, opal is indeed a legitimate gemstone. The International Gem Society recognizes opal as one of the major precious gemstones along with diamond, ruby, sapphire, and emerald. In fact, opal has been valued for its beauty and rarity since ancient times, and has been used in jewelry and decorative objects for centuries.
One argument against opal being considered a “real” stone is its relative softness compared to other gemstones. However, hardness is not the only factor that determines whether a substance is classified as a mineral or not. For example, amber is also a mineraloid that is not crystalline yet it is still considered a legitimate gemstone.
Another argument is that opal’s water content makes it more fragile and prone to cracking than other stones. While it is true that opal requires special care to prevent drying out, this does not detract from its beauty or value. In fact, opal jewelry is often admired for its unique rainbow-like hues and is highly sought after by collectors and enthusiasts.
Conclusion
In conclusion, opal is indeed a legitimate gemstone that has been prized for its beauty and rarity for centuries. While it may have some unique properties, such as its softness and water content, these do not detract from its value or legitimacy as a gemstone. Whether you prefer the bright orange hues of fire opal or the intense flashes of color seen in black opal, there is no denying the beauty and allure of this unique mineraloid.
