Elucidating the broad classes of Gemstone – Octobers Opal: Precious and Common.
One of the Bradley Hatch team’s favourite gemstones is undoubtedly OPAL – Its beauty and wave of colour tones means it comes as no surprise that we have an ever-flowing footfall of customers coming into our store in search of the perfect OPAL. Thankfully, we have just the collection.
So, let’s get technical for a moment. What is it? Opal is a hydrated amorphous mineraloid form of Silica with a water content ranging from 3-21% by weight. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl and basalt. Cool or what!
There are two broad classes of the Opal gemstone: Precious and Common.
Precious opal displays play-of-colour creating an iridescent look and is the primary gem form for this stone. It creates a "pseudo chromatic” optical effect resulting in flashes of coloured light from certain minerals, as they are turned in white light. The internal structure of the precious gemstone causes it to diffract light, resulting in this play-of-colour. It can flash every colour of the spectrum with an intensity and quality of colour that surpasses the fire of diamond.
This is something common opal does not display.
Instead common opal has its own variety of milk, milky blue/green, resin opal – of which is a honey-yellow with a resinous lustre, wood opal, menilite of brown or grey colour, a colourless hyalite and many others forms. Common opal often displays a hazy-milky-turbid sheen from within the stone.
Depending on the conditions in which it formed, opal may be transparent, translucent, or opaque and the background colour may be white, black, or nearly any colour of the visual spectrum. Black opal is considered to be the rarest, whereas white, grey, and green are the most common.
Essentially, the darker the tone of the opal, the more valuable it is. This is because when the body tone is darker, the flashes of colour are more pronounced. What you’re really paying for is the sharper and more intense colours emanating from the stone. The gorgeous patterns may also determine its worth. Generally speaking, the larger the pattern, the more valuable the stone becomes. Keep these things in mind, as unlike diamonds, there is no rule that a larger stone will be more valuable.
So, what about maintenance? Opals are particularly delicate gemstones, like pearls. They must be maintained properly as overtime it can scratch, making it appear duller. However, do not fear. Our expert team can professionally polish the stone for you, reviving its brilliance. But, in the meantime wash it with warm water and store in cotton wool with a few drops of water when not in use.
A gemstone with a history of being prized by royalty in Europe.
