Types of opals
Be very careful when buying solid opals as technology has improved and confused the market. Synthetic or lab opals as they are also known are sometimes sold and masqueraded as the real thing by some unscrupulous dealers. If they look a bit too good for the price then be suspicious and have a good look at the pattern. Synthetic opals are very uniform in pattern. Natural Opals are not totally uniform in colour and pattern. All my Opals are guaranteed natural Australian Opals.
I will not go into the full details of every type of opal, colour and value, as there are a multitude of web sites out there where you can find this information. Instead I will just give a basic overview of the main types available from GEM N I and from which parts of Australia. Other types of opal are available from other countries such as Mexican Fire Opal and Welo opal from Ethiopia but not nearly as stable as Australian Opals.
These opals originate from Lightning Ridge in New South Wales. Some of the worlds most unique and prized opals are from these opal fields. Valuable opals particularly with bright red on a pure black base are highly sought after. Close to Lightning Ridge is Grawin (officially known as The Grawin). Opals from these fields are usually blue and green but occasionally a black or grey base shows up with beautiful colours. I should add at this point that a black opal is not always ‘jet’ black. Anything darker than a white opal is also termed a black opal. Black opals basically have a darker body tone. They come in many forms and in order of value: Nobbies are the most sought after followed by, crystal, semi crystal and jelly, in that order.
White opals or white base opals are mainly found in the South Australian regions of Coober Pedy and Andamooka. They are also found at some other sites in New South Wales such as White Cliffs. Although not quite as highly sought after as Black Opals many people prefer these as they can be more subtle but still have amazing brilliance and colour. A very bright gem grade white opal with plenty of colour, particularly reds or orange (see below, ‘Colours’) can be worth a lot more than a basic black opal.
This originates in Queensland and is opal in an ironstone base. They can be very beautiful and a lot of carving is done with these opals. GEM N I doesn’t sell these opals currently. One problem with these opals is that the opals make a complete mess when cutting water mixes with the ironstone substrate.
My only comment is – nature does it better!