There’s plenty of diamond jewelry online these days, and you want to ensure that the diamond you buy is authentic and has the quality you wanted (and bought). It’s important to keep a few points in mind when you’re browsing loose diamonds or diamond jewelry online: A more sensitive version of the Standard Presidium, above; and the design has been 'squished' to the size of a standard diamond tester. This has both an anlogue meter operated by a probe ('thermal' tester) and a digital meter (for refractive index/reflectivity). There are pros and cons of both types. In summary, the digital meter will test 40 stones, but it will only test loose stones (not stones set in jewellery) and you have to be careful and clean to get a correct reading; the analogue meter is very easy to use (on loose stones and on set stones) but only tests 17 stones, most of which have overlapping readings:

If you’re selecting a lab-created or natural diamond, make sure it’s certified by renowned institutes such as IGI and GIA. Certified diamonds are a good way to ensure authenticity, and they also come with details about the quality. So if you are testing a really tiny stone and get a reaction, it's probably diamond (test it again, turn the sensitivity right up). Easy to use, compact and sturdy, the Presidium diamond testers provide accurate and consistent results every time. Presidium Gauge PLEASE remember that Moissanite shows up as DIAMOND on simple diamond-only diamond testers. So if you already have a diamond tester, buy a Moissanite tester, if you don't have a tester at all, go for a Multi Tester, it will detect diamond and distinguish diamond from Moissanite. latest technology, this is the only tester of this sophistication that is pen-size, operated with one hand, slips into a pouch (supplied)gives higher readings (1.00 to 3.00) and this enables it to test for diamond and for simulants such as Moissanite

if you are quite happy to work slowly and carefully in laboratory-clean conditions but you must have a machine that will positively identify any stone: such a tester does not exist When you have finished all your testing, remove the probe from the tester and put it safely away in its case. works on any stone, you are not limited to jewellery that will fit over the sensor, you are not limited to transparent stones with a flat top (table), they even work on 'rough' (uncut) stones.Whenever anyone asks if a tester is "100% guaranteed to identify all diamonds" I take a deep breath. There are always always always exceptions. And these apply to all brands of diamond / Moissanite / multi testers. To test if a diamond is real, you will need to place the tip of the tester on the stone’s surface and detect the rate at which heat or electricity moves through the gem. If the diamond is genuine, the device will indicate that on the display and give a sound signal. What Type of Diamond Tester Is Better? You will not get correct readings if, in that first split second, you remove-and-replace the probe or slide it across the stone or press hard then let go then press hard. It only works if you put the probe on the stone (in the centre of the stone) firmly - once. As with all of these testers, this is no problem if you can see what you are doing and you have a steady hand. If you can't see, please find your reading glasses or a magnifier. If you don't have a steady hand you will not be able to use a tester. Too complicated? Then do not buy a gem tester (or if you do, please do not buy it from us). Sounds interesting? - then go for it! NOTE: in the jewellery trade, "Diamonds" and "Gemstones" are regarded as separate industries. Diamond testers ( see separate article) are more precise since they are fine-tuned for testing diamonds only.

Firstly, a very rare type of diamond (imaginatively named Type II). These are indistinguishable from other diamonds. It's merely a quirk of their chemical composition that they happen to be electrically conductive - which is why they register MOISSANITE on multi testers. These are rare, you might never come across one, but they do exist, they turn up regularly at gem laboratories, to settle disputes arising from the use of testers. Secondly, some synthetic diamonds (genuine diamonds, but grown in a laboratory rather than dug up from the ground) can read 'diamond' and 'Moissanite' on different parts of the stone. you know, from your experience, that a customer is offering you paste, he says it's white sapphire, you need to show him the result on a machine, because customers believe machines rather than expert humans. To to see all the advantages and disadvantages of a "Digital Refractometer (reflectivity meter)" scroll down slightly. The only difference is that this (Duo Presidium) displays a two-digit number you must look up on the Presidium chart whereas the "Digital Refractometer (reflectivity meter)" below displays the reading as 'refractive index', a standard system that gemmologists understand (see any text book or search the internet).For the non-expert: if it has any colour (e.g. the tiniest slightest yellow tint) you won't get an accurate reading. It takes an expert to colour-grade a stone, to the non-expert Colour Grade D will look exactly the same as Colour Grade J. For the professional jeweller: if you work at a shop counter and don't understand this, please ask your diamond expert to colour-grade the stone for you. if you understand the limitations of gem testers but there really is no way you have time to keep the tester meticulously clean and clean every stone before every test, and you cannot guarantee that it will never be bumped or dropped or get dusty or damp. Opt for the latest model: technology is constantly changing everywhere, and that’s the same for diamond testing detectors as well. The latest models combine heat and electricity testing for the greatest accuracy.