Identifying Gutta Percha, Bog Oak, Jet and Vulcanite has long plagued antique jewelry aficionados. This blog will help you separate these substances in no time!
When I got a question on my Facebook page about how to identify these substances and what the differences were between some of them, I was as happy as a kid in a candy store. I got to look into books I hadn’t picked up in years and even go online to the really geeky sites on things like the History of Plastics. It was my own little nerd fest of one.
I was asked some really serious questions about identification so I’m going to get a bit technical, but it will be worth it, I promise. When I’m done, you’ll be picking out gutta percha from vulcanite and bog oak from jet to the amazement of all your friends.
Let’s start with Bog Oak since it’s one of the easiest things to identify. First, Bog Oak isn’t just oak. It can actually be three different wood species: Pine, Yew and Oak. Each of these turns a different color after thousands of years of exposure to tannins in bogs so the color itself is a good way to identify it. Oak changes to an almost black color, yew changes to a reddish brown and pine turns a golden yellow. None of the other substances are a golden yellow or reddish brown so if it’s one of those two colors, it’s bog oak.
Second, all those species of wood will have one thing that the other substances will never have: growth lines! Trees grow and we are all familiar with the growth rings of trees. If you look at bog oak jewelry, you will see growth lines with a standard 10x power jeweler’s loupe. Since none of the other substances will have growth lines, bog oak is the easiest to identify.
Third, the subject matter will give away bog oak very often before you even take a closer look. Bog oak jewelry often has an Irish motif so you’ll encounter jewelry like shamrocks, harps, and castles.
Now, start thinking about how jewelry is made from each of these substances. Bog Oak has to be carved so you are going to see tool marks on any jewelry that’s made from bog oak.
JET: The only other of the four substances that’s remotely natural and therefore carved is jet. Jet is like “petrified” wood, but according to GIA, it’s a form of lignite coal. It’s decayed wood that was compressed under layers of sediment and pressure to form a coal-like substance. Jet started to form in the Jurassic period. Bog oak became what it is only a couple thousand years ago. That’s a huge difference. Whereas with bog oak, you can still see that it is wood, in the case of jet, it’s not really wood anymore. It’s more like stone than wood so you won’t see growth lines. Jet can take a very high polish so you will see a surface more like glass. Since glass was the biggest imitator of jet, you have to worry more about mixing up jet and glass than mixing up jet and other Victorian jewelry substances like gutta percha and vulcanite. The picture below from Mourning Glory Antiques shows the high polish of Jet.
The real question here should be “How do I tell the difference between jet and glass?” That’s a simpler answer than you would expect also. I read a secret with jet a long time ago. Jet used to be called “black amber.” It was not only found alongside amber in alluvial deposits, it reacted like amber. Amber, if you will remember from my video blog on How To Identify Amber Without Damaging It, will develop static electricity when rubbed on wool or silk. You can use the static to pick up small bits of paper. The same is true of jet! Jet will develop a static charge and also pick up small bits of paper. So tear up some paper to test for jet. Another test for jet is to rub it on the unglazed or rough edge of the bottom of a porcelain cup. Jet will leave a black streak on the porcelain but glass will not. Glass is also cold to the touch and jet will be closer to room temperature. By the way, “French Jet” is glass.
That takes care of the “carved” materials. I say that because knowing how these things are made and what they are made from will help you identify them. Bog oak and jet are carved. Anything carved will have tool marks. If it has tool marks, it’s either bog oak or jet. The color of the material will help you separate them, along with the presence or lack of visible growth lines.
Now… gutta percha and vulcanite.
Gutta percha is a sort of latex or resin derived from the tree sap of various trees in the Pacific Rim. It was one of the first thermoplastics and is historically important because of that. Interestingly, little jewelry was made from gutta percha. Most of the gutta percha went into “functional” things like buttons, wax seals, belts, boot soles and according to the History of Plastics website, a lot of golf balls in 1848. If it’s jewelry, it is RARELY Gutta Percha.
Gutta percha is light sensitive and has a tendency to turn brown with exposure to light (and oxygen) over the years. Most of the gutta percha jewelry seen today is brown and not black like it was originally. The color is a clue to its material nature. Unless it was hermetically sealed after it was made, it will have been exposed to light and OXYGEN. What is not exposed to oxygen?? It will therefore have turned a brown-ish color. Gutta percha is also molded, not carved, so there won’t be any visible tool marks on the piece. Since it’s basically a rubber-like material, it will smell like rubber when it’s rubbed briskly on fabric. The most effective way to tell if your jewelry is gutta percha is to TASTE IT. Seriously. Please wash it before and after tasting it and in fact, taste it at your own risk. But if you choose to taste it, it will taste salty. If it doesn’t taste salty, it’s not gutta percha.
Vulcanite is the last of the materials. Another rubber-like substance made from more tree sap mixed with sulphur, it will also be molded and not carved.
The bracelet above from the Art of Mourning is a perfect example of molded jewelry. Look closely at the cross and the possible cluster of grapes (?) under the oak leaves. Do you see how rounded the edges are? Anything carved would have a much sharper edge. That “rounded-ness” is a sure way to tell if something is molded.
Most of the jewelry that you see identified as gutta percha is in reality mis-identified vulcanite. Vulcanite can also turn to a khaki brown color like gutta percha; will smell like rubber when rubbed on material; and also leave a brown streak on the unglazed bottom of a porcelain cup. You can tell the difference between vulcanite and gutta percha by choosing to taste it. If it’s salty, it’s gutta percha. If it’s not, it’s vulcanite. More often than not, it will be vulcanite. Like I said, most of what you will see as gutta percha will actually turn out to be vulcanite, so if you skip the taste test and call it vulcanite, you will probably be correct. Vulcanite will most often remain black in color while Gutta Percha will turn brown-ish. If you need to be 100% certain, go ahead and bite the bullet so to speak!
Now you know more than anyone should ever know about alternative Victorian jewelry materials and small sporting balls. You may now go forth and impress antique store owners and golfers with your new found knowledge.
If you have jewelry made from any of the materials in this blog, I want to hear from you! Send me a picture of how you wear your jewelry on my Facebook page or post it and tag me on Instagram. I’d love to feature you wearing your jewelry in an upcoming blog!