Hi all again,
As we bunker down in the middle of this awful carona virus, I thought I might take this opportunity to slightly further the interesting thread around doublets. My workshop
I think you guys nailed the definition of a doublet in the earlier thread, but there was a little blurring around ‘blackening agents’ and inlay.
Doublets as already established are a composite of two layers, the opal layer and a backing. The most common backing (commercially cut) is ironstone (boulder opal host rock). The opal is glued to the ironstone usually with two pack glues with a blackening agent added (the Asians use nigresene powder). Other smaller niche cutters, which I now call myself after years of being one of the true bad guys (full blown mass production), use Lightning Ridge black potch, is or black obsidian (as I do). These last 2 don’t require the use of any blackening agent, although the Lightning Ridge cutters still seem to insist on using a blackening agent.....for the life of me I don’t know why...totally unnecessary and detracts from the bond integrity.
Before I go into inlay, I want to talk a bit more about doublets.
If you have read through the previous doublet thread and pics posted there, you will see I make a fair bit of noise about the thickness or thinness of the opal layer and I talk about opal content.
Technically any thickness of opal can be called a doublet so long as the opal layer on top is the polished part and the face of the stone...(no glass cap). If you troll sites like the opal auctions site, you will find hundreds of thousands of commercial doublets ...pretty cheap. These are all cut in China, backed with ironstone with a very thin veneer of opal. They are flat on top and all contain a blackening agent.
These doublets are prone to chipping and breaking when setting into bezels, which is why 90% of doublet jewellery you see on Etsy or eBay sees the stones glued in...not properly set. Even the sellers selling Lightning Ridge Black solids set stones this way...not always to be fair, but it is pretty common and easy to pick if you look closely.
Then there are doublets cut with thicker opal layers, using better backings as referenced above. Generally, they are far superior, depending on the process and the cutter.
I use obsidian as I have stated and shown in the other thread. I have tried everything over the years including manufacturing several hundred thousand ironstone backed doublets. Nowadays I only cut my own opal, and I use obsidian exclusively...this is why.
I have referenced several reasons in the other thread...won’t repeat what I said so go read that if you are interested. Apart from that though I will go further here.
Obsidian as we know is a naturally occurring volcanic black glass. I use black obsidian. I like it because I can get a variety of translucency as discussed in the previous thread, from fully opaque sliced at 2mm to a lighter more translucent look that allows much more light through the finished stone, and still looks dark. Obsidian gives the finished stone a completely natural look and brings the opal to life adding depth and light to the stone. The finished look in jewellery is stunning..I will post a couple of pics later to show you.
That brings me to the term inlay, infill, and blackening of opal and jewellery settings, and for what it’s worth my opinions on all.
Firstly let’s talk about inlay. Opal inlay continues to be popular despite most of it now being made from synthetic blue green opal. There are still some people that make opal inlay jewellery with a variety of success and quality. Without disparaging the work of the very few fine artisans that make stunning pieces which I will get to in a minute, the vast majority of inlay jewellery is a disaster just waiting to happen. It is just not a good idea to lap opal down to inlay thickness which is generally thinner than 1mm and glue it straight into metal inlay settings with a blackening agent behind the opal and sitting in the setting. Nearly all inlay has squared sides and sharp corners...again a disaster waiting to happen, especially in rings that have a habit of getting hit into hard objects occasionally.
There are some exceptions. Some of the old school highly skilled inlay artisans will curve the inlay slice (use round wheels on fixed arbors) to match the curve of the opal with the curve of the ring setting. These guys know who they are and my hat has remained off to you guys...and one very clever gal whom I won’t embarrass on here. These guys are true artisans, and make very fine quality pieces, and they get a lot of money for their pieces (because they use much thicker opal and spend much more time making the inlay more secure ...plus their obvious dedication to quality).
When you see the term inlay, it generally means the opal has no backing apart from a blackening agent, or black epoxy between the stone and the setting (absolute disaster in my book). Some opal people will use the term ‘inlaid opal’ in jewellery. This often can mean that they have used a doublet, and have glued it into a bezel setting. I don’t really understand why they call it that, perhaps they perceive the term inlaid is held in higher regard to the word doublet.
We occasionally will make a piece of jewellery that is in essence a form of inlay, or at least designed to have that streamlined look. What I do, is back the opal onto obsidian as per a normal doublet, and I take the backing down pretty thin, generally about 1 to 1.5mm depending on the thickness of the opal layer. I like the completed thickness to be around 2 mm minimum...which is twice as thick as the average inlay at least.
We ( I really mean Jenni ...she is the clever jeweller not me...and I cut them as per instructions), seat down the settings to as close to flush as possible. We can’t fully replicate the inlay look as Jenni has always insisted on setting even small rings like this into proper bezels, meaning that the stone/s are properly set and will not chip or break.
We manage to set some reasonably sharp shaped stones such as squares or cornered stones using this technique. The stones are proper doublets, and are carefully cut to ever so slightly soften the edges and the corners. They look sharp, but they feel nice and soft in the fingers if you pinch them. With a bezel around them they are good to go, and will last the distance.
Some of you are probably wondering why I would bother to go this effort.
I am sad to say that there are a lot of miners and very poor cutters in Australia passing themselves off to you guys and the world consumer, as self professed opal experts and professional cutters.
We have spent most of our lives building our knowledge and experience the hard way. We lived for 20 years In Coober Pedy, and we have quietly been mainstream wholesale supplies for many years. Jenni did her jewellery apprenticeship over 4 years and required us to travel 7 times a year by car with our young family driving through the desert to Adelaide a trip of over 850km each way. We had to rent a flat, and stay for a week each time, so Jenni could complete the academic side and pass her technical tests to become a fully qualified jeweller. She is a gifted jeweller and won the South Australian apprentice of the year award in her final completing year.
It drives us nuts when we see dodgy, poorly cut stones, and even worse jewellery, especially coming from self pronounced opal experts from Australia.
I can tell you guys (Americans), I have spent a lot of time in the US, and have given a lot of my time guest lecturing to final year university students studying jewellery, to help them gain confidence and understanding about using opal.
I have been in more jewellery workshops in the US than I can count, and am always thrilled and encouraged by the American artisans, especially the lapidary guys out there. From my experience the American cutters are far more knowledgable and much better skilled than just about all of the opal people here in Australia!
I am really passionate about opal, opal jewellery and in particular the merits of well made opal doublets.
For my money, they are sensational value, and are an absolute premium product if cut right....
I guarantee all my doublets for life against lifting (delaminatiin). They are water resistant rated to 1000hours of continuous immersion ( meaning the glue doesn’t even start to break down until that point. I can soak them in metho for cleaning...doesn’t touch them, and they are completely safe in the ultra sonic.
Thanks for reading, and I hope that I might continue to help everyone improve their opal outcomes and further their addiction!
I will include a couple of pics of Jenni’s recent doublet jewellery...and one green orange solid ring.
Mike