2019年10月11日 · The presidium gem tester is not considered to be very accurate. You don't see serious gemologist using them. If I was to own just one tool it would be a refractometer.

2010年4月30日 · Does the Presidium Gem Tester or other refractometer instruments identify natural versus synethic stones? I purchased some stones (not expensive but not dirt cheap). The seller insist they are natural because she tested them with the presidium gem tester. I thought that it identified the stone species but not if it is natural or synethic. Thoughts?

2011年5月2日 · I just bought a brand new Presidium Multi Tester III Diamond/Moissanite tester so I could test for diamonds on my jewelry collection. I was told it was top of the line and the best I could buy. It's been a nightmare. Even on pieces I know …

2020年6月22日 · I've had a Presidium Gem Tester II for a couple of years and find it is reliable and performs exactly as the manufacturer claims. It's relatively easy to use, and gives accurate results if you follow the manufacturers instructions, and ensure you have good contact between the probe and the surface of the gem.

2008年6月29日 · while pawnshops generally don’t have a resident gemologist they always make use of a Presidium gem tester, mostly to sort out CZ from diamonds, blue topaz from aquamarine and any coloured/ treated quartz or glass gems from anything else.

2011年4月14日 · It tests as "spinel" on my presidium gem tester so....hence the description. And as you can see by the price I am assuming faux sapphire. I know blue spinels cost a LOT, and this may be a steal if it really is spinel... which is doubtful. But anyway, back to the question at hand. Could a gem tester mistake a synth sapphire for spinel?

2012年1月29日 · On a Presidum gem tester, a Moissanite should test as “diamond”. This is because their thermal conductivity is similiar. A CZ will always “test” as glass on a Presidium. If your Moissanite is clean and still registering other than …

2017年3月24日 · I have a pair of diamond jackets that I wear with various colored gemstones and pearls but wanted something diamond-like. Given the cost of 2ctw diamond studs (and wanting something similar I could actually afford) I purchased white zircon studs off eBay after seeing previous forums on...

2009年5月1日 · I have a Presidium gem tester which has its limits. It can not distinguish between man made and natural. So it’s not “the answer”. I used to use it for IDing white stones” ie CZ, white topaz, white sapphire and diamond but it can’t tell me if my white sapphire is Natural or man made. It can tell Spinel from ruby and garnet.

2019年10月26日 · The big problem with using any gem tester (I have the expensive Presidium) is its use is very limited. It can’t distinguish between lab grown material and natural from the earth. The gem testers are best for IDing say CZ vs other gemstones. On a presidium both sapphire and topaz have the same thermal signature.