GUIDE TO BUYING DIAMOND TESTERS

Diamond, Moissanite and Multi testers; UV lights and testing diamonds; buying diamonds and how to avoid scams
e.g. buying cheap diamonds directly from the mines in Africa, fake diamond crystals, Phenakite
Includes Quicktest testers, Gemtrue and Diamond Selector.

 

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THIS ARTICLE: CONTENTS

Are diamond testers foolproof? The tale of a man who was fooled

Diamond testers and UV (ultra violet) light

Moissanite and Type II diamonds. Moissanite and UV (ultra violet) light

Recommendations, model by model - reviews

Conclusion - go to this section if you just want to know the best one to buy

Test results

Newspaper article by Raffi Katz about diamond testing

Related articles


ARE DIAMOND TESTERS FOOL PROOF - THE TALE OF A MAN WHO WAS FOOLED

The following story is a warning to anyone who thinks that having a machine (any machine) is guaranteed to get them a bargain.

We sold a diamond tester to a man who went to Africa to buy 'bargain' diamonds (uncut 'rough' diamonds) from a 'contact'. After a very long time haggling they agreed a price (I think it was $50,000.00), he tested the stones, they registered DIAMOND on the tester, they were sealed in a container and the he signed across the seals. The money was transferred into the seller's bank account and the following day the buyer collected the stones. The seals on the container were still intact. And guess what? When he got them back to England he found they weren't diamonds at all. The customer rushed the diamonds over to us, we tested them on five different diamond testers - they were not diamonds.

This, in a way, was a clever 'con' - because the average jeweller will know what a cut diamond looks like, and if presented with huge stones that look 'too watery' or 'too sparkly' he will be suspicious, even before turning on the diamond tester. But very few people know what diamond crystals look like. If you are planning on parting with thousands of pounds, do some research and find out - click here to visit a web site selling genuine uncut diamonds, this is what diamond crystals should look like.

There are other precautions you can take if you are spending large amounts of money and know nothing about diamonds.

Firstly, if the deal seems too good to be true, it's because it is too good to be true, "Cheap Diamonds" are like "cheap gold" or "cheap cash" - they simply don't exist...unless you become involved with criminal gangs. These gangs (according to the many press reports) smuggle real diamonds, drugs and people, and you really do not want to find yourself in a remote part of the world, taken by gunmen to remote mines, then pressurised into parting with money.

Do not let that diamond tester out of your sight, even for a minute. They can be tampered with (by re-soldering wires inside) so that everything reads DIAMOND. Our man in Africa managed to return to England without the diamond tester, it had been "mislaid in the confusion" - what a surprise!

Keep on your person a genuine diamond (it need not be large) and a paste (glass) and a sapphire (a small synthetic sapphire will do) and test each of them before testing your purchases. You will then know if the diamond tester has been tampered with.

It is also possible, with any machine made by man, that the machine develops a fault - so use those three stones to check the machine.

Tricksters have been known to store stones in ice to cool them so that the diamond tester falsely reads DIAMOND. Try touching the stone gently against your upper lip to see if it feels icy cold, try clasping it in your warm hand and chatting to the sellers for five minutes. If they become agitated it might be because the stone is rapidly reaching room temperature and is about to register NOT DIAMOND on your tester.

These precautions do not apply to everyday dealing where the amounts of money involved are relatively small, there is no need to become paranoid. And I did sell a diamond tester to someone who was going to Africa, but who had recommendations from friends who lived there, and he was happy about who he was dealing with and, as far as I know, the transaction was successful. Whether he made a profit I have no idea.

BEWARE OF UNUSUAL STONES...AND ALWAYS BE AWARE OF THE OBVIOUS

One stone that caused prolonged correspondence on an internet forum for gemmologists, was an unknown stone bought as 'black diamond'. It was opaque, so the usual examination of inclusions, under a microscope, was not possible; the surface was 'pitted' like granite; the SG (specific gravity) wasn't quite right; and although it certainly registered 'diamond' on a diamond tester, the results on a Moissanite tester were inconclusive, it depended on where, on the stone, the probe was placed.

Even without a gemologist spending a few hours examining and testing the stone, there were two causes for concern. Firstly, it was bought by a serviceman in Afghanistan, and most stones sold to servicemen in this area are not genuine. Secondly, 'proof' that it was natural black diamond came in the form of a lab report (certificate) from New Delhi, from "an ISO 9001:2008 Company comprising GIA alumni." A certificate is worthless unless you can check that the company (and the certificate) is genuine - and even then, you need the skill to match the stone with the certificate.

Gemmologist's conclusion: it was not diamond, it was Moissanite.

My conclusion: electronic testers are not suitable for user on black stones.


DIAMOND TESTERS AND U.V. (Ultra Violet light)

Some models of diamond tester have a built-in UV light, and this has led to the quite logical assumption that UV light can be used for testing diamonds. This is not true. There is absolutely no way you can distinguish diamond from non-diamond using UV light. The only useful thing to know is that diamonds fluoresce (glow) randomly.  So if you have a cluster ring or a diamond brooch and all the stones react in exactly the same way (whether they fluoresce or not) - they are probably not diamond; if some fluoresce and some don't...then they might be diamond..or they might not.

UV light can, however, give an indication of probability when comparing natural diamonds with synthetic diamonds (see 'Explanation' at the bottom of this section). For examining 'parcels' of diamonds you will need a UV lamp that provides long-wave AND a short-wave UV light. View the stones on a black background in a completely dark room (or a viewing cabinet). Natural colourless diamonds (of which about 40% fluoresce) usually fluoresce more under long-wave than under short-wave; some synthetic diamonds have just the reverse reaction, the fluorescence is weak (or nil) under long-wave, and  strong (or stronger) under short-wave. So if you buy loose diamonds, check each parcel under UV light to judge the probable mix of 'naturals' and 'synthetics'. But examining a diamond under a UV light tells you nothing. This information is for the gemmologist or professional diamond dealer, the average jeweller or antiques dealer does not need to know any of this.

UV light can also be useful when grading a diamond for colour, because white diamonds that fluoresce under UV light also fluoresce under UV light present in daylight, and this can make the stone appear a better colour than it really is. Again, this information is for the gemmologist or professional diamond dealer, the average jeweller or antiques dealer does not need to know any of this.

Explanation:'Synthetic' does NOT mean 'imitation' - a synthetic stone is grown in the laboratory to the same recipe found in nature, and the aim of the manufacturer is to make an end-product which is identical to its natural counterpart. Synthetic diamond IS diamond (unlike, for instance, Cubic Zirconia or Moissanite which are not diamond) - and synthetic diamond registers DIAMOND on diamond testers...because it IS diamond.

MOISSANITE

Moissanite (read all about it) is a manmade stone (it doesn't exist in nature in a form that can be cut into gemstones*). It is not common, it was only 'invented' in the 1990s, its only significance is that is registers 'diamond' on diamond testers. Moissanite does, to the non-expert, look remarkably like diamond - but it is not diamond it is Moissanite, i.e. Moissanite is not a 'type' of diamond, it is another stone altogether.

* It's found either as tiny black crystals of Silicon Carbide or as tiny green platelets. You can see pictures of Moissanite crystals here, they are less than 1mm in size and cannot be cut into gemstones. Part of the publicity about Moissanite is true: that the French chemist Henri Moissanite (hence "Moissanite") discovered the mineral in a meteorite crater in Arizona in 1893. But the gemstone stems from a 1998 patent for "translucent silicon carbide of a single polytype that are grown in a furnace sublimation system" (i.e. it is grown in a furnace, it does not exist in nature) - and you will notice that, for the sake of the patent, it is known as "Silicon carbide gemstones" rather than the more romantic name "Moissanite". You've probably heard of Silicon Carbide under another name, it is synthesised to make the abrasive 'Carborundum'.

MOISSANITE TESTERS AND TYPE II DIAMONDS

Moissanite testers work by measuring electrical conductivity through the stone. Diamond is not electrically conductive, Moissanite is. However, there is a very rare type of diamond (Type II diamonds) which has an unusual chemical composition (it does not contain nitrogen, it contains boron) and this makes the diamond electrically conductive, i.e. it will register 'Moissanite' on a diamond tester.

If you are not a diamond dealer handling thousands of diamonds, it's unlikely that you will ever see one of these. But, rare as these diamonds are, they are turning up at gem laboratories, sent in by anxious retailers following complaints by their customers (who have bought an expensive diamond only to find it registers 'Moissanite' on a Moissanite tester). We do have a tester that will check for Type II synthetic diamonds, model SDS, but it is a very specialist item for testing known diamonds and should not be confusesd with a diamond tester.

MOISSANITE TESTERS AND UV (Ultra Violet light)

Unlike diamond testing, UV light does make a difference when testing a Moissanite on a Moissanite or combination (multi) tester.

The discovery was made by a gemmologist who worked out that, according to the laws of quantum physics, UV light should make a difference to electrical conductivity. He then took a deep breath and set about finding out just which exact wavelengths of UV light were required. To his amazement he found that any UV light would work. Moissanite testers that don't work on some 'difficult' Moissanites (rare as they are) work perfectly when the stone is exposed to UV light.

If you are buying a Moissanite tester, buy a UV light too, they really are not expensive (see how UV light works). If you are buying our combination (multi) tester, there is a UV light built in to the tester, and this is the only model that will enable you to shine the UV light on the stone whilst testing (other models give you the choice of testing the stone or using the UV light, but not both at the same time, which isn't really of any use).

 

DIAMOND TESTER OR MULTI TESTER?

A diamond tester (altenatively known as a diamond-only tester) will distinguish diamond from non-diamond with the exception of a manmade stone called Moissanite, which will register 'diamond'.

A multi tester will tell you if you have: diamond / not diamond / Moisssanite (and, with the Experior model, ruby and sapphire too).

I used to say that Moissanite wasn't common, you were unlikely to come across it.

Moissanite is a manmade stone (read all about it), it was first made in the 1990s. I used to say that if you knew you had an old item that predated the invention of Moissanite, then the stones could not be Moisssanite; that if you dealt in antique jewellery you would recognise genuine antiques that were too old to be set with Moissanite.

This is what I used to say.

However, as the years pass, Moissanite has become more common. It has now been around long enough for there to be lots of second hand Moissanite jewellery. It has now been around long enough to be passed down to the next generation, who aren't too sure if it's Moissanite or diamond. It has now been around long enough that most people who are interested in jewellery have actually heard of it.

For all of these reasons, I would now recommend a multi-tester rather than a diamond-only tester, so that you can distinguish diamond from Moissanite.

However, mulit testers are quite expensvie compared with diamond-ony testers and we do still sell large numbers of diamond-only testers. A diamond-only tester will certainly tell you if a stone if neither diamond nor Moissanite, and therefore definitely not diamond. So if you only want to know when a stone is definitely not diamond, then a diamond-only tester is fine.

 

DIAMOND TESTERS (diamond-only testers) - BEST

Each blue link takes you to the product, where you will find full technical details plus a review. Below is a very short summary.

DT-5 Quicktest diamond tester

Advantages:

- we have extended the number of LED light segments from 8 to 9.

- the chart on the back of the tester shows sizes of diamonds as circles actual-size, rather than a grid of figures.

- we have completely re-written the instruction manual so there is no need to battle with a free translation from Cantonese or Japanese. We have re-labeled the controls, the knob is now correctly labeled 'Sensitivity' rather than than the confusing 'Volume'. The new labeling also makes it clearer as to which lights indicate 'diamond'.

- we have 'tweaked' the specification so that it can't give a false 'diamond' reading on large rubies and sapphires (and any large cold stone). see the test results. This gives you the option of using it outside in the winter (e.g. in outdoor boot sales, markets and antiques fairs) and still get correct readings, or to be able to test any cold stone and get correct readings, see the test results. Most diamond testers are simply not designed to work in the cold, and in China (where these are made) their idea of 'cold' is 18 degrees C.


Disadvantages:

- we have turned the sensitivity DOWN, so the reaction is sluggish on very tiny diamonds. We consider this a good price to pay for the sake of getting correct readings in difficult conditions.

 

DIAMOND TESTERS (diamond-only testers) WORTH CONSIDERING

Each blue link takes you to the product, where you will find full technical details plus a review. Below is a very short summary.

DT-4 Quicktest diamond tester (with UV light)

Advantages:

- it’s the more sensitive of the two diamond testers, really tiny stones react decisively
- it has a UV light (some people like this)

Disadvantages:

- in common with 99% of diamond testers on the market, it’s very sensitive, in really cold conditions large stones tend to register ‘diamond’, see the
test results.
- it has a UV light (this serves no purpose when testing diamonds)

 

DIAMOND TESTERS (diamond-only testers) - CHEAPEST

Each blue link takes you to the product, where you will find full technical details plus a review. Below is a very short summary.

The Diamond Selector is a very cheap Chinese copy of a tester what was made in Japan, there are many factories in China making these, some use the cheapest of components and they rarely work, some (like ours) use good quality components and they work most of the time, but you must be aware that you get what you pay for, see the test results.

 

MULTI TESTERS - BEST

Each blue link takes you to the product, where you will find full technical details plus a review. Below is a very short summary.

There are two big 'known' names, Gemvue and Presidium.

MULTI-EXPERIOR (diamond / Moissanite / Ruby-Sapphire tester). As a compromise between best price and good performance (you'd have to spend twice as for the Adamas, below) I'd recommend this one, and it's the only mult-tester that will also show ruby and sapphire too. See our test results.

Presidium Multi Tester III (model PMuT III) There is no doubt that this is one of the best (most consistent in its readings, and most reliable) tester on the market, both Presidium and Gemvue each say theirs is the best, my personal view is that they are as good as each other. The Presidium is slightly smaller and neater and far more expensive. Unfortunately, this one is now discontniued. We have a handful remaining (as of Spring 2017)
- the Presidium Multi Tester II (model PMuT III) has been replaced with the
Multi-Adamas. This is the most beautifully-designed tester and (in our tests) was the best of the multi-testers, but it is incredibly expensive.



CONCLUSION:


To cover all possibilities, the MULTI-3 will also distinguish Moissanite, which registers diamond on diamond testers. If you really have no idea about diamonds, you should be spending that extra little bit for one of these.

If you already have a diamond tester, there's no need to buy a MULTI tester, there is a tester just for Moissanite.

If you are a dealer and are reasonably confident about identifying diamonds, and just want 'confirmation', then choose one of these diamond testers:

- if you ever work out in the cold or if you often come across large stones or if you intend to buy uncut crystals or if you are worried about false ‘diamond’ readings - go for the DT-5,.This is my favourite, it has been designed especially for QUICKTEST, it minimises the chance of getting 'diamond' readings on non-diamonds.

- for a good all-rounder choose DT, it is fine providing you don't use it in very cold conditions or test very cold stones. This also has the advantage of price, being part of a 'job lot'.

 

 

TEST RESULTS

The following charts show the test results when testing stones in the cold.
Diamond testers work using ‘heat’.
Cold stones often give a ‘diamond’ reading, even if they are not.
So a measure of a good diamond tester is how well it can cope with this.

When studying these charts, it is important to remember that the tests were carried out on some unusual stones in cold temperatures. If you are working in the warm and testing small stones, the testers will perform much better.

KEY

These are ‘difficult’ stones most likely to fool diamond testers, in reality you might not get to test stones like these:

- RUBY: a very large ‘boule’ of synthetic ruby, (20 ct by weight).

- PHEN: a crystal of Phenakite (12 ct by weight) – these are used to ‘scam’ people into thinking they are buying uncut diamonds, they read ‘diamond’ on most diamond testers. Phenakite is not used as a gemstone, it is too soft and looks absolutely nothing like diamond. Incidentally, crystals of Phenakite look nothing like diamond either. But the scammers target people who don’t know this. For our purposes, we like to test something that behaves just like diamond on the testers.

- SAPP: a white sapphire (5pts on a spread gauge) bezel-set in silver, to make it ‘cold’


CHART 1

Working indoors: what happens if a customer brings in a stone that’s been out in the cold?

You need to wait for it to warm up.

But for how long?

Here, the stone temperature was 5° (left in the fridge overnight, so it had completely cooled).

The room temperature was 18° so the stones warmed up slowly. If the room temperature had been in the mid to high 20s, the stones would have warmed up quickly.

After 5mns left in the warm

After 10mns left in the warm

After 15mns left in the warm

After 20mns left in the warm

  Ruby Phen Sapp   Ruby Phen Sapp   Ruby Phen Sapp   Ruby Phen Sapp
DIAMOND-ONLY TESTERS                              
DT5 (Quicktest)
OK
OK
OK
 
OK
OK
OK
 
OK
OK
OK
 
OK
OK
OK
DT4 (Quicktest)
OK
fail
OK
 
OK
OK
OK
 
OK
OK
OK
 
OK
OK
OK
Diamond Selector (a good one)
fail
fail
fail
 
fail
fail
fail
 
fail
fail
OK
 
OK
fail
OK
Diamond Selector (a cheap one)
fail
fail
fail
 
fail
fail
fail
 
fail
fail
fail
 
fail
fail
OK
MULTI TESTERS
 
 
 
Adamas
fail
fail
OK
 
OK
fail
OK
 
OK
OK
OK
 
OK
OK
OK

Multi Experior

fail

fail
OK
 

OK

fail
OK
 

OK 

fail
OK
 

OK

OK
OK

 

CHART 2

Working outdoors: you can’t let the stones warm up.
Here, the air temperature was 2°, the stones had been outside in this temperature for one hour.
The testers were warm (I shall assume the tester had been in the user’s pocket).
Diamond testers are simply not designed to work at these low temperatures, so these were tough tests.
The only one to pass all the tests was the Quicktest DT-5.

Tester model

Stone

 
Ruby
Phen
Sapp
DIAMOND-ONLY TESTERS
OK
OK
OK
DT5 (Quicktest)
OK
OK
OK
DT4 (Quicktest)
OK
fail
OK
Diamond Selector
(a good one)
fail
fail
fail
Diamond Selector
(a cheap one)
fail
fail
fail
MULTI TESTERS
Adamas
fail
fail
OK

Multi Experior

fail

fail
fail

 

CHART 3

As above, air temperature 2°, but this time the testers were cold too (as if the user had left it on an outside market stall or was carrying it in a bag).
In these extreme conditions none of the testers coped with Phenakite and the Adamas failed to start up (the power light flashed for a minute then the power cut off).

Tester model

Stone

 
Ruby
Phen
Sapp
DIAMOND-ONLY TESTERS
DT5 (Quicktest)
OK
fail
OK
DT4 (Quicktest)
OK
fail
OK
Diamond Selector
(a good one)
fail
fail
OK
Diamond Selector
(a cheap one)
fail
fail
fail
MULTI TESTERS
Adamas
Tester failed to warm up
Tester failed to warm up
Tester failed to warm up

Multi Experior

fail

fail
fail

 

CHART 4

Room temperature 16° (I’d guess that the stones could have been a degree or two cooler).
This could be a typical temperature of a shop / unit in Northern Europe early on a cool day, before the heating has had time to take effect.

Tester model

Stone

 
Ruby
Phen
Sapp
DIAMOND-ONLY TESTERS
DT5 (Quicktest)
OK
OK
OK
DT4 (Quicktest)
OK
OK
OK
Diamond Selector
(a good one)
OK
fail
OK
Diamond Selector
(a cheap one)
fail
fail
OK
MULTI TESTERS
Adamas
OK
OK
OK

Multi Experior

OK

fail
OK

 

 

NEWSPAPER ARTICLE ABOUT DIAMOND TESTING

Here is an article, by Raffi at Quicktest, originally published in the Antiques Trader newspaper:

 

I once walked into a local shop (it sold crafts and coins and the odd antique…and little bit of jewellery) and I said, "Hello Edward" (he didn't like being called "Ed") and I showed him one of our small battery-operated diamond testers. 

 

"Why would I want one of those?" he said, pointing to a handful of stone-set rings in his window.

 

Upon testing the first four rings this is what he found.  The first (labeled 'paste') was not diamond, the second (labeled 'diamond') was not diamond, the third (labeled 'diamond') was diamond, the fourth (labeled paste') was diamond - he bought the diamond tester.

 

Again and again customers at the fairs say, "If only I'd had one of these last week when I was buying a 'parcel' that contained stone-set jewellery!"  

 

We sell most of our diamond testers by mail and customers don't actually make a special point of writing to say how wonderful it is - but there are very few complaints.  In fact, the latest diamond testers are so reliable that virtually all complaints concern dogs ("The diamond tester worked fine until the dog chewed it") or tea ("I don't know WHY it doesn't work any more, do you think it might be because I spilt tea in it?") or the Bermuda Triangle ("I lost it").

 

Long ago a diamond tester was a big square box of electronics with a probe, you plugged it into the mains, waited two minutes for it to warm up, pressed the probe on the stone, waited for a reaction, and they were expensive.

 

Today a diamond tester is small (the size of a tube of toothpaste), takes one standard battery, you wait twenty seconds for it to warm up, press the probe against the stone, and get a reading immediately.  And they are not expensive.

 

Many customers say, "How does it work?"  I never answer the question because they don't usually mean "How does it work?" they mean, "How do you work it?.  But I shall answer both questions.

 

HOW DO YOU WORK A DIAMOND TESTER?

 

Switch on, hold it like a pen, wait for it to warm up (when the READY light shows), press the tip onto the stone, if the row of LED lights light up quickly (and there's a bleeping sound) then you have a diamond, if the lights don't move at all it is not diamond, if the lights move very slightly you probably have a ruby or sapphire (though a diamond tester is not designed as a ruby - sapphire tester).   There is also a safety feature that sounds an alarm if you accidentally touch the mount instead of the stone (which avoids false readings).

 

HOW DOES IT WORK?

 

Heat.  Or, to be more precise, Thermal Conductivity.  You may have seen traders 'testing' stones to see if they are paste or 'real' by touching the stone against the lip.  They are feeling (not very scientifically) for  "coldness."  Plastics (and maybe glass) feel warm-to-the-touch, many gemstones (probably) feel cold to the touch, as I say, it's not very scientific.  This relative coldness is what the tester is measuring, Thermal Conductivity.

 

ARE THERE DIFFERENT TYPES OF DIAMOND TESTER?

 

The most common type of diamond tester works on the principle of Thermal Conductivity.  There are two slight variations.  The cheaper models have two lights, one for Diamond and one for Not Diamond, the best model has a row of lights.  The advantage of the better model (row of lights) is that you can turn the sensitivity down if you are working in the cold (e.g. an early morning market), the cheaper model (two lights) will give false readings if it is cold. 

 

HOW RELIABLE ARE DIAMOND TESTERS? - WHAT ABOUT CUBIC ZIRCONIA AND MOISSANITE?

 

Of the two most common diamond simulants, Cubic Zirconia (including 'diamond-coated' Cubic Zirconia) presents no problem at all but Moissanite needs a special mention.  Moissanite is a purely synthetic stone (ie it is grown in laboratories by man) and it registers as diamond on  diamond testers. This is an unfortunate fact of physics, that Moissanite has the same thermal properties as diamond.  So how do you tell Moissanite from diamond?  There is another  electronic tester, it looks (and operates) just like a diamond tester though it works on an entirely different principle.  Or there is a combined electronic tester for diamond and Moissanite. 

 

Do you need a diamond tester and a Moissanite tester?  Most people buy only the diamond tester; most people buy the diamond tester "just to start with" and some buy the Moissanite tester. Do you really need a Moissanite tester?  Here are two fascinating facts that might help you make your decision:

 

FACT 1.  Moissanite was first commercially grown ('invented') by man, so if you are quite certain that you are testing an antique ring (that hasn't been tampered with) then the stones won't be Moissanite. The origin, as a mineral (Silicon Carbide) found in meteorites, dates back to 1893 but cannot be used as gemstones, quite contrary to the publicity that implies that this is a rare as-good-as-diamond gemstone that comes from outer space. Not true.

 

FACT 2.  Moissanite hasn't quite taken off in the way that Cubic Zirconia did, probably because the smallest Moissanite costs several pounds whereas Cubic Zirconia costs a few pennies, so Moissanite isn't that common.  However, it's main purpose (it seems to me) is to fool antiques dealers, usually with a story about the item of jewellery having been in the family for many years.

 

So if you are trawling the fairs and boot sales and are happy that the items you see are genuinely old, you will probably be OK with just a diamond tester, but if you set up shop and advertiser that you buy jewellery you will attract the fraudsters, so make sure you have a Moissanite tester too.

 

Finally, there are testers that will test both diamond and Moissanite (i.e. one tester to test both). The advantage is that you only need one machine instead of two, and also it costs slightly less to buy the combined tester rather than two separate testers. The disadvantage is that you do have to follow the instructions precisely (unlike diamond-only testers which are very simple to operate).

 

Whichever you choose, you will need good eyesight (good enough to see the tip of the tester and the very centre of the stone) and a steady hand. I have watched many people who have neither of these attributes and will never, ever, be able to use a tester, at best they 'sometimes' get it to work.

RELATED ARTICLES

The complete guide to testing diamonds

Distinguishing diamond from Moissanite

Diamond tester trouble shooting

A lot about electronic gem testers

A little about optical gem testers

 

 

 

 

 
QUICKTEST, Watford, WD18 8PH, Tel. 01923 220206, email info(at)quicktest.co.uk