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How To Test Jade Under UV Light (And What It Tells You!)

where to find jade in california

How To Test Jade Under UV Light

Jade’s high value has led to many imitators and treatments, with a battery of tests deployed by those interested in the stuff. There’s one test that few people seem to have a good hold of, however, which is testing out jade underneath a UV light. It’s a little bit more involved than a simple positive/negative test but it can be an invaluable tool for identification.

So, let’s get into it and I’ll teach you how to test jade under a UV light and what kind of further testing may or may not be needed!

What Does UV Light Do to Jade?

Nothing. Absolutely nothing happens on a piece of untreated jade when you hit it with a UV light. In 99% of cases, there should be absolutely no reaction in a piece that hasn’t received any treatment.

Ultraviolet testing is only one of the many tests available, but it’s a quick one. Especially if you already know the material is jade but you’re just trying to determine whether or not the piece has been treated.

The takeaway here is that jadeite jade, as a general rule, does not fluoresce without an outside treatment. From repeated experimentation, it appears that occasional inclusions will glow but these should only be a speck or two in an untreated piece.

So, you essentially have four rough grades of jade to be aware of:

  • Grade A- Untreated or just waxed on the surface. Rare, very expensive, and usually 100% unreactive to ultraviolet light.
  • Grade B- Chemical treatment/bleaching before the piece is impregnated with some form of polymer. Usually reacts strongly to UV light. Grade B treatment increases clarity and color.
  • Grade C- Dyed and stained jades fall into this category. Many dyes are UV reactive and light up. Grade C treatment usually makes the stone a bit more opaque and may lead to unnatural color zoning in poorly dyed examples.
  • Grade B+C- Jade that’s been chemically treated, dyed, and filled with a polymer.
  • Grade D- Not always included on grading lists, Grade D jadeite is a composite mixture of crushed jade and some form of resin to create a reasonable facsimile of jade.

Grade D jade is rarely sold as the other grades, it doesn’t take a lot of experience with stones to figure out that a bangle or pendant that weighs less than it should and possesses a plastic feel isn’t the real deal.

UV testing for jade isn’t a conclusive test, remember that when testing. It’s most useful for a known piece of jade that you think may have undisclosed treatments.

Not all treatments show up under UV light either, you should also administer a specific gravity test at a minimum in order to be sure you’ve got the right material in your hands.

So, How Do I Test My Jade With UV Light?

It’s pretty simple to set up this test at home. Begin by finding something non-reflective and non-reactive to ultraviolet light to place on a surface. I have a bit of black cloth that fits the bill, but not every cloth is equal.

You need to use a long wave light, short wave lights don’t always react properly when you’re doing this test. 

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Many cheap dyes will fluoresce under UV light, so a lot of cloth is unsuitable. One other big problem with using cloth is that detergents with brighteners usually contain UV-reactive components.

Lay your piece of jade on top of this and spotlight the material with your UV light. Then pay close attention, results are pretty much immediate.

You’re looking for a green glow, like that of a glowstick.

This is usually how it breaks down:

Grade A material should not react. A few tiny specks of bright green material can be inclusions but 99% of the material should not fluoresce. You may also run into the occasional crack or fracture that got wax pressed into it that didn’t come off during polishing, you can sometimes tell by faint fluorescence that appears on close inspection.

Grade B material will usually react. The fillers are generally UV-reactive, but not every resin or epoxy used in the process will be. That said, not all fillers are reactive and Grade B may require a microscopic inspection to detect.

Grade C material will almost always react. The majority of dyes used to color jade are UV-reactive and will light up like a glowstick as soon as the UV light hits them.

Grade D material is immediately recognizable in hand. If it feels like plastic… it is, crushed pieces of jade mixed in notwithstanding.

If there’s no reaction then you probably have a good chunk of untreated jade on your hands as long as it came from a reputable source.

Ultraviolet light testing is great, but it’s not a definitive test for the presence of jadeite. It just rules out a couple of possible treatments.

Note that some jade will have a very weak yellowish reaction to UV light without treatment, especially in white areas. It will be quite obvious if the material fluoresces, don’t get too worried about trying to track down super faint glowing in your piece.

Other Tests for Jade

A few other tests can help you be a bit more certain about what you have. These tests are a little more difficult to perform, as a general rule, but they’re valuable for those looking to be 100% sure of what their sample is.

Density/Specific Gravity

Specific gravity testing should be one of your go-to tests for identification, and it’s the first to engage in for most people. Scratch testing in order to determine hardness will affect the finish of the stone after all.

But jadeite is a rock, which means it’s not a pure mineral so it has a wide range of acceptable specific gravities.

In this case, it’s best to go with what the experts say. GIA considers 3.33 g/mL the cutoff for real jade. That is: if the specific gravity is 3.33 or higher then you’ve most likely got actual A-grade jadeite on your hands.

The easiest way to do this is just to pick up a specific gravity testing kit, which works with an electronic scale. Frankly, if you’re regularly around gemstones and need to know what they are… these kits are pretty much essential.

Hydrochloric Acid Testing

You can put a small drop of HCl on the stone, preferably somewhere you can’t see any damage, and then observe it under magnification.

The HCl will begin “sweating” and beading on a natural piece of jade as its pulled into the capillary system between the grains of material. GIA has a good section on this in their document on detecting treated jade.

This test is pretty definitive, but it does require using strong acids and magnification.

Beware Color Tells

I’ve heard it repeated time and time again that jade is natural if it has brown in it. After all, part of the process that Grade B jade goes through is chemical bleaching.

This is incorrect. Jade is an expensive stone and that always creates a bit of an “arms race” between buyers and unscrupulous sellers. So you have treatments… and then you have more treatments to hide the initial treatments once their tells have become widely known.

A few brown spots and people are a lot less likely to verify what they’ve got. A brown dye is used to keep people from looking too close on occasion, so don’t use it as the sole means to verify if your piece is jade or not.

Jeremy Hall

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