Diamond Tester for gemstones results

[Goldenco]

Hi there,
Is the diamond tester accurate in identifying all sapphires and rubies? Is it possible to distinguish sapphire from tanzanite?

Same question for presidium.

 

[Bron357]

Not really. The Presidum uses thermal conductivity so it can broadly distinguish between different gemstones on that basis. However, there are countless synthetics out there (some better than others) ie ruby and sapphire which are man made from the same chemical composition as real rubies and sapphires. So it can’t distinguish between man made corundum and natural.
Tanzanite on a Presidum has a lower thermal conductivity than sapphire so it can differentiate between the two.
It can ID “glass” gemstones, it could ID tanzanite coloured corundum (ie man made corundum).
So a Presidum can be used as a tool but what you really need is a Loupe and an understanding of what the “real” gemstone looks like to better ID the fakes. The biggest problem these days is that some treatments and procedures require a laboratory analysis to be sure, so it’s best to buy from reputable sources and/ or gems with proper certification.
99% of the gems on eBay are synthetic, glass filled or BE treated, despite what the sellers say, and despite their “fake” certificates they are only worth a few dollars only.
Buyer beware.

 

[Goldenco]

Ok thanks.
What's about the diamond selector tester for gemstones?

 

[Bron357]

Ok thanks.
What's about the diamond selector tester for gemstones?

Again, those type of testers are notoriously unreliable and can only tell diamond from CZ. They aren’t suitable for coloured gemstones.
Only a Presidum is properly calibrated to differentiate between gemstones and they cost a couple of hundred dollars to buy. Those $20 types, like from eBay, are not reliable.

 

[Sam jersi]

This diamond selector for for gems other than diamonds is worthless. I tried it with a filled glass ruby and it was positive test, it went all the way up and the piece was worth $10. Plus gems needs some one to take a look at them with loops and light, you need to know your gems, you can't just use this DS tester.

 

[Burmesedaze]

No. My jewellers with 20 years in the business tell me they are quite useless given the synthetics out there.