December 14-16—SAN DIEGO, CALIFORNIA: Wholesale and retail show; Gem Faire Inc.; Scottish Rite Center, 1895 Camino del Rio S; Fri. 12-6, Sat. 10-6, Sun. 10-5
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 Post subject: Hard and soft moissanite?
PostPosted: Wed Dec 22, 2010 1:40 am 
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Dear guys,

I have recently saw a new diamond/moissanite tester from Tri-electronic that claim they can accurately identify for hard (high resistance) and soft (low resistance) moissanite. 'Hard' moissanite suppose to have high resistance similar to diamond therefore it can't be correctly identify by ordinary testers. I am just wondering if there is such 'hard' and 'soft' available? Thank!


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 Post subject: Re: Hard and soft moissanite?
PostPosted: Wed Dec 22, 2010 2:00 am 
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Never heard of "soft" or "hard" moissanite :-k . The best place to learn what you need to know is probably here.

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 Post subject: Re: Hard and soft moissanite?
PostPosted: Wed Dec 22, 2010 2:54 am 
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Moissanite is not identified by how hard it is, (how would this device test for hardness anyway?...resistance to what?), but by it's very obvious optical properties, (it has high birefringence, giving doubling of some facets when viewed at the right angles through a microscope and high dispersion giving much greater fire than diamond when viewed at the right angles). It is also cut differently than diamond and has an odd color. Once you've seen a few of these you can pick them out quite readily. Oh, they also glow bright orange with fairly low heat...not that you'd want to take a torch to a clients jewelry, but it is odd the first time you work on a piece and a couple of the melee turn color like that.

In any case, I think those electronic devices are a very poor replacement for being able to look at something like this and tell what it is. I would avoid that device and get some moissanites, (try pawn shops or jewelers for chipped or broken stones), so that you can become familiar with them. Education always beats relying on cheesy tools with BS for advertising claims.

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 Post subject: Re: Hard and soft moissanite?
PostPosted: Wed Dec 22, 2010 11:21 am 
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Michael makes excellent points.
May I suggest someone call Tri-electronic and ask them to explain what they mean.

Michael, you're a good candidate for that phone call, because you have a good understanding of what a thermal tester can test for and what it can't.

Let us know.
:D


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 Post subject: Re: Hard and soft moissanite?
PostPosted: Wed Dec 22, 2010 2:30 pm 
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This is the text of one of their retail sellers online ads,
"this is the first tester to include a patent-pending Calibration Block that will allow the user to test for Metal, low-resistance moissanite, high-resistance moissanite, diamonds, and simulants using small test pads that imitate thermal conductivity and electrical resistance. The Calibration Block can be used to ensure the accuracy of the tester without the need for buying expensive test stones and diamonds.

This is a state-of-the-art multi-stone tester with new photoconductivity technology that can detect any type of moissanite. Identifies all of the following: Diamond, moissanite, simulants and metal. The tester has distinctive visual and sound signals for each position. It features fast warm up, instant recovery between tests, and extended temperature range."

I find this very interesting as I have never heard of high and low resistance moissanite, (though I imagine that it could be associated with some type of coating that some seem to have to make them appear more colorless). I have also not heard of photoconductivity, but that to might just be a longer word for, "clarity", we'll see.

I am not much for phone calls, as I seem to spend hours on the phone talking to the wrong people, but I am interested and so have sent them an E-mail asking for some further clarification about what the terms they are using mean and how they are measuring them. I am not negative towards this product and it may have some use. I don't think that it will replace knowledge or thinking, but if it actually works well it would be nice to know that it could be used as an indicator for further detailed investigation of a stones other properties. I hope they answer my inquiry and I'll post back when they do.

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 Post subject: Re: Hard and soft moissanite?
PostPosted: Thu Dec 23, 2010 2:03 am 
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Thanks


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 Post subject: Re: Hard and soft moissanite?
PostPosted: Thu Dec 23, 2010 8:35 pm 
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Barbra Voltaire wrote:
May I suggest someone call Tri-electronic and ask them to explain what they mean.

Michael, you're a good candidate for that phone call, because you have a good understanding of what a thermal tester can test for and what it can't.

Let us know.
:D


O.K., here's the deal. I ended up calling Michael at Tri Electronic and this is what he said:

Moissanite is a semiconductor and has two levels of electrical resistance. The low level is called "soft" and the high level is called "hard". Their tester measures both thermal conductivity and electrical resistance. While diamond has similar thermal conductivity, it's electrical resistance is dramatically lower than moissanite.

They also claim to measure "photoconductivity". I asked about this and was told that when you shine a light from an LED on moissanite, the surface electrical resistance is reduced and that this does not happen in diamond.

I don't have one of their testers and so can't say anything about how they operate or make any remarks one way or the other about whether these effects actually exist. Perhaps someone more involved in the electrical properties this material can chime in.

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 Post subject: Re: Hard and soft moissanite?
PostPosted: Thu Dec 23, 2010 11:01 pm 
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Interesting. I suspected it was something like that.

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 Post subject: Re: Hard and soft moissanite?
PostPosted: Fri Dec 24, 2010 4:02 am 
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Dear guys,

Thanks for all your replies. Cheers! Merry christmas :)


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Zen


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 Post subject: Re: Hard and soft moissanite?
PostPosted: Wed Jan 05, 2011 4:17 pm 
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http://www.adamasgem.org/mouse.html

As has been the case so often, Martin Haske has been way way ahead of the curve.
He was involved in the design and testing of the Moisketeer which is probably what the
Tri Electronics unit copys in its high voltage test section. The page on Marty's site linked to above has been up for years and years. The Moisketeer was a good tester but failed commercially. (PS a jewelry supply place I frequent here in St. Louis had one on display for sale. It might have been sold. The name of the place is National Supply. http://www.nationalsupply.com )

All moissanite is doubly refractive and is going to exhibit facet doubling at some easy to find orientation. It also is separated with visual optics (The Hodgekinson method) pretty easily.

Charles and Colvard also have a tester that distinguishes transparency to LLW UV light.
It has a quartz halogen bulb and a photodetector with a UV filter.

Marty also makes and sells a UV transparency outfit. More elaborate and expensive than C&Cs Very old news.


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 Post subject: Re: Hard and soft moissanite?
PostPosted: Wed Jan 05, 2011 5:23 pm 
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G4Lab wrote:
http://www.adamasgem.org/mouse.html

As has been the case so often, Martin Haske has been way way ahead of the curve.
He was involved in the design and testing of the Moisketeer which is probably what the
Tri Electronics unit copys in its high voltage test section. The page on Marty's site linked to above has been up for years and years. The Moisketeer was a good tester but failed commercially. (PS a jewelry supply place I frequent here in St. Louis had one on display for sale. It might have been sold. The name of the place is National Supply. http://www.nationalsupply.com )

All moissanite is doubly refractive and is going to exhibit facet doubling at some easy to find orientation. It also is separated with visual optics (The Hodgekinson method) pretty easily.

Charles and Colvard also have a tester that distinguishes transparency to LLW UV light.
It has a quartz halogen bulb and a photodetector with a UV filter.

Marty also makes and sells a UV transparency outfit. More elaborate and expensive than C&Cs Very old news.


Thanks Gene..

SiC (moissonite) absorbs light below about 430nm (I can't remember the exact number and am too lazy to look up the spectra right now.) That was the basis for the C3 optical tester, but the detector probe had to be in physical normal contact with the stone's table so you wouldn't get reflected light into it.

The ex President of Charles and Covard told me I cost them over a million dollars by pointing out that Testorite(TM) {my knickname for it, as they would initially sell a stone sample without buying a $500 tester} was electrically conductive, and they had to dump their optical testers on the market because of their auditors.

All moissonite is electrically conductive, to varying extent, the Moiskeeter 2000SD looked at leakage current, NOT BREAKDOWN voltage as the early testers did. (Look at a current versus voltage graph, breakdown is when the current flow jumps up dramatically) The trouble is, the purer you make it (SiC), the higher the breakdown voltage, which could be up over 1000Volts, according to the literature. CERES still sold their 300volt breakdown voltage tester, EVEN AFTER I PERSONALLY GAVE THEM THE RESEARCH DATA (with a tunsten carbide scribe, what a joke and fraud in my opinion, through Kessler). They did go belly up for a different reason later and a French company bought them out,as I understood, served them right.


Stay away from dual testers, as the maker of the 2000SD found out when he said not to use his on corundum (in small print) COLD AL2O3 will FAIL thermal testing, depending on the size of the stone. I pointed that out on Polygon, and he went belly up very soon after as over 1000 orders were canceled.

I can't comment knowingly on the photoconductivity issue.

USE YOUR EYEBALLS and a microscope, look through the crown mains to see the doubling on the pavilion facets.

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 Post subject: Re: Hard and soft moissanite?
PostPosted: Sun Jan 09, 2011 7:17 am 
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adamasgem wrote:
USE YOUR EYEBALLS and a microscope, look through the crown mains to see the doubling on the pavilion facets.


AMEN to that!! 8) :D
ciao
alberto

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 Post subject: Re: Hard and soft moissanite?
PostPosted: Thu Feb 10, 2011 12:44 am 
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adamasgem wrote:
USE YOUR EYEBALLS and a microscope, look through the crown mains to see the doubling on the pavilion facets.
But that doesn't look as cool as having a device that has blinking lights and beeps at me. How am I going to impress a potential customer without flashy devices that have huge flaws in their abilities to actually provide pertinent data? I mean really. :twisted:


Sorry I just had too. :oops: :D Thank you for taking some time to explain a bit more about what these devices limitations are.

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 Post subject: Re: Hard and soft moissanite?
PostPosted: Thu Feb 10, 2011 1:20 am 
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JREFaceting wrote:
adamasgem wrote:
USE YOUR EYEBALLS and a microscope, look through the crown mains to see the doubling on the pavilion facets.
But that doesn't look as cool as having a device that has blinking lights and beeps at me. How am I going to impress a potential customer without flashy devices that have huge flaws in their abilities to actually provide pertinent data? I mean really. :twisted:


Sorry I just had too. :oops: :D Thank you for taking some time to explain a bit more about what these devices limitations are.


You just gave me an idea for a universal customer BS machine, along the lines of the old magic 8-ball
:wink:

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 Post subject: Re: Hard and soft moissanite?
PostPosted: Thu Feb 10, 2011 12:14 pm 
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