Buying opals loose in a store is difficult enough if you don't understand them, but buying them online is a daunting task. You are at the mercy of the seller and that is not always in your best interest. But I can help you with a few tips that will make your journey easier.
Natural or synthetic?
Synthetic opals are artificially produced in a laboratory and most websites will call them "engineered opals". They can also make amazing galaxy opals. They may also be called "imitation opals."
Solid, Doublet or Triplet?
Let's say that after deciding that we want real or natural opals rather than synthetic opals, we now have to decide whether we want a solid opal, a doublet or a triplet.
You may know that solid opal is one piece and is the best and most expensive.
A solid opal that is very thin, too thin to make a piece of gold opal ring, will have an additional piece of black opal glue on the back to give it strength and reflect the light colors of the stone. They are doublets and are cheaper than solids and can often look even nicer. We just have to realize that they are not solid opals.
A triplet is essentially a doublet with a dome made of a clear material such as quartz or glass. They are the cheapest of all, but often look fantastic. Again, we just have to understand what we are buying.
Doublets and triplets don't just have to be thin or low-quality opal products that can't be sold. Sometimes good opal is intentionally cut into small flat pieces to create doublets and triplets. For a true opal lover like myself, this is a curse. I've seen these thin wafer pieces cut so thin that when you put them in the palm of your hand, they sink into the hollow of your hand. From one original massive opal, they are then made into lots and lots of triplets.
What is the best color?
Let's say we want a natural, solid opal. Another thing to think about is color. Anything with a red color will be the most expensive. Then there is expensive green and then blue. But having said that, I have seen a lot of bright blue solid opals that are much nicer and much more expensive than the boring bits of red. So it's more about how bright and fiery the actual opal necklace is than whether it's red, blue, green or any other color.
What shapes should I be looking for?
As most good opals come from Australia, you will see their dimensions in millimeters rather than inches or fractions of an inch. Most opals will be oval in shape. For many years, the market dictated that oval shapes were the most popular. If it is not an oval shape, then it will be called "free form." This means that it is an irregular shape.
This is an important distinction because the ovals are more likely to go into a setting that your jeweler already has, rather than having to make a setting specifically for this freeform stone, which will cost you much more. Maybe twice as much or more than a mount that was mass produced and freely available to your jeweler.
Does size matter?
What you want to know is the size first. If it's for a ring, then you'll be looking for a 7x5mm oval, or 8x6mm, or 10x8mm, or even 9x7mm. These are the sizes that your jeweler might have a ring ready for your stone. Otherwise, he will have to have one custom made.
The size of the pendant can be from 8 x 6 mm and larger. I think anything smaller than this is a touch too small for a pendant.
Another thing you want to know is the thickness of the stone. Generally, any opal less than 1.5mm thick will be too thin. Opal thicker than 4mm can be difficult to set in a ring.
Of course, I am generalizing here. I put 18 x 13 x 6mm solid opals in the rings, but they were big.
What about inclusion?
You also want to be aware of any inclusions or blemishes on the top surface of the stone. Stones like emeralds, sapphires and diamonds have what we call inclusions. If you look closely at the stone, you will see some cracks, small holes, discoloration and other things. These depreciate the stone, but usually do not make it unsaleable.
Opals are different. It is okay to have a pitted surface on the bottom of the opal or a bit of what we call sand. This is sometimes mixed with the opal structure and the cutter makes sure it is the bottom or under the opal.
