sssurfer Posted July 12, 2006 Report Share Posted July 12, 2006 I recently purchased on ebay a tool set composed with two tools: the Diamond Selector II and the Moissanite/Diamond Tester. (WARNING: there are replicas of those tools around ) They are primarily intended to distinguish diamond from synthetic diamond (moissanite) and other imitators, but the seller claimed they are able to tell sapphire from glass too, and they were priced about 1/3 - 1/4 of other similar professional tools, so I decided to give them a try. Well, they work. They told all my 4 sapphire crystals and 8 glass crystals. As I had to do some web searches and some trying to figure out how and why they work, here I am sharing my small experience with all members. First of all: to detect diamond from imitators they are to be used together, but to detect sapphire from glass each of them proved reliable on its own, so one can use them to confirm each other. Diamond Selector II: This tool works by measuring the thermal conductivity of material (that of sapphire is higher than that of glass). 1 - Turn the instrument on by rotating the Off/On/Volume wheel. 2 - Wait for the "lamp on ready ok" led lightens. 3 - Rotate the Off/On/Volume wheel until the color scale shows all 4 green sectors lightened (this is not critical, less sectors or more sectors are also ok, but this way makes it easier reading the scale later). 4 - Touch the crystal with the tool's tip placed vertically. Glass does not make any further sector lighten on the scale, or at most 1. Sapphire makes 3 or 4 further sectors lighten on the scale. Moissanite/Diamond Tester: This tool works by measuring the electrical conductivity of material (that of sapphire is lower than that of glass). The instrument emits a low current, that usually has to go through the examinator's body to re-enter into the tool. So, in theory, the examinator has to touch the object in test by his left hand in order to close the circuit. But in practice this is necessary only for small objects like gems; for bigger objects like watch crystals the object's mass is enough to dissipate the current even if the circuit is not closed. Anyway, if one wants to be sure not to get sapphire as a result when it is glass instead, he'd better follow the following instructions also in points 2 and 3. 1 - Turn the instrument on by rotating the Off/On wheel (it does not matter how much you rotate it, once it is On it just affects the sound volume). 2 - Hold the tool correctly, with your right forefinger on the button on the backside, so to also touch the metal plate around the button. 3 - Hold the crystal with your left hand, or - if it is already on a watch - simply touch it. If you don't want to leave fingerprints on it, touch it with a metal object you hold in your hand, like a pair of metal pliers. 4 - Touch the crystal with the tool's tip placed vertically and push the button. Glass makes the red leds lighten (possibly after a brief flash of the green leds) and sound a beep. Sapphire makes the green leds lighten (possibly after a brief flash of the red leds). In any case, after 2 seconds the measurement stops. ------- For the curious, here are some physical values: Thermal conductivity (W/m/K): Diamond: 630-1000 Sapphire: 32-35 Glass: 0.8-0.93 Electrical resistivity (Ohm/m): Diamond: 10^16 - 10^18 Sapphire: 10^16 Glass: 10^10 - 10^14 Quote Link to comment Share on other sites More sharing options...
mikellem Posted July 12, 2006 Report Share Posted July 12, 2006 ssurfer, Excellent imfo...Thanks! Think I am going to buy one also.. Quote Link to comment Share on other sites More sharing options...
ubiquitous Posted July 12, 2006 Report Share Posted July 12, 2006 Very informative posting! Great stuff! Quote Link to comment Share on other sites More sharing options...
Chronus Posted July 12, 2006 Report Share Posted July 12, 2006 I have one already but paid around the price you paid just for one of them And yes it does work. I also tested glass in a window, and also genuine watches with and without AR coat. Quote Link to comment Share on other sites More sharing options...
Linder Posted July 12, 2006 Report Share Posted July 12, 2006 I too have heard this was possible but did not understand it and was afraid to spend the money on just a theory. Thank you so much for the detailed explanations! Quote Link to comment Share on other sites More sharing options...
dabom Posted July 12, 2006 Report Share Posted July 12, 2006 I find the water test to be 100% accurate for me. The water test is so accurate that I really don't need to spend $75 on any other tool. Glass is more sticky than sapphire, so when you put a drop of water on glass and roll it around, you'll find it sticking to most of the surface of the glass. With sapphire crystal, you'll find that the water will bead. Works every time. Quote Link to comment Share on other sites More sharing options...
Chronus Posted July 12, 2006 Report Share Posted July 12, 2006 I find the water test to be 100% accurate for me. The water test is so accurate that I really don't need to spend $75 on any other tool. Glass is more sticky than sapphire, so when you put a drop of water on glass and roll it around, you'll find it sticking to most of the surface of the glass. With sapphire crystal, you'll find that the water will bead. Works every time. Good for you Quote Link to comment Share on other sites More sharing options...
kingkitesurf Posted July 12, 2006 Report Share Posted July 12, 2006 I find the water test to be 100% accurate for me. The water test is so accurate that I really don't need to spend $75 on any other tool. Glass is more sticky than sapphire, so when you put a drop of water on glass and roll it around, you'll find it sticking to most of the surface of the glass. With sapphire crystal, you'll find that the water will bead. Works every time. Can you post pictures of the two different results? Thanks. Quote Link to comment Share on other sites More sharing options...
dadog13 Posted July 12, 2006 Report Share Posted July 12, 2006 tnx for the info sssurfer...it is a cheap way to see what is the quality of our crystals.... does it show if it has the "Light AR coating"... Quote Link to comment Share on other sites More sharing options...
ehtolcad Posted July 12, 2006 Report Share Posted July 12, 2006 when i get my watches i get in my car and drag the crystal across the pavement. if it scratches, i know i have glass and if it doesn't i know that i can wear it. Quote Link to comment Share on other sites More sharing options...
sssurfer Posted July 12, 2006 Author Report Share Posted July 12, 2006 Removed Quote Link to comment Share on other sites More sharing options...
KB Posted July 12, 2006 Report Share Posted July 12, 2006 So from now on whenever someone asks how to tell Sapphire From Glass we can say "send it to sssurfer" Ken Quote Link to comment Share on other sites More sharing options...
yt74 Posted July 12, 2006 Report Share Posted July 12, 2006 Wow, yet another thing I feel compelled to buy! But seriously, thanks for the great post. Quote Link to comment Share on other sites More sharing options...
MAHLER Posted July 14, 2006 Report Share Posted July 14, 2006 (edited) Perfect and very useful article !!! A picture of one your tool : ...stupid question delete... Edited July 14, 2006 by MAHLER Quote Link to comment Share on other sites More sharing options...
sssurfer Posted July 14, 2006 Author Report Share Posted July 14, 2006 Removed Quote Link to comment Share on other sites More sharing options...
sssurfer Posted July 14, 2006 Author Report Share Posted July 14, 2006 ...stupid question delete... Ooops... too late! ...Not such a stupid question anyway. Quote Link to comment Share on other sites More sharing options...
MAHLER Posted July 14, 2006 Report Share Posted July 14, 2006 (edited) Ooops... too late! ...Not such a stupid question anyway. excuse me... but I have to get away the habit to ask stupid questions... thanks for the gentleness in to answer me. I have tried to put the photo of the second tools but imageshack is inexplicably closed always therefore I have abdicated. Edited July 14, 2006 by MAHLER Quote Link to comment Share on other sites More sharing options...
sssurfer Posted July 14, 2006 Author Report Share Posted July 14, 2006 Wow, this is almost a chat session! Quote Link to comment Share on other sites More sharing options...
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