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#1

Prospectinglife
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Joined: 10 June 2016
Posts: 19
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22 December 2016 04:12 pm

I have these gems that all show a really positive reading from an ebay gem reader. They show a better reading than the clear red zircons i have. They are all clear some upto 92 carats but arent clear like the sapphires you see from wal n liz on there videos or from grabben gullen.1482383514_fb_img_1482383095204.jpg

#2

Jaros
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From: S.E.Qld., QLD
Joined: 11 August 2013
Posts: 5,654
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22 December 2016 05:45 pm

What would you like to know.
Jaros


Lottsa hope :F1A4M2, Exterra 705 Gold, Ace 250,Aldi detector, ? detector,Garmin Etrex30, 2 sieves,2 pans,2 sluices, Nugget sniffing Cocker Spaniel. X-Pointer PI by Deteknix, Jobe Knife, Leschke Shovel, Pro-swing 45 Harness, Treasuremate 11 Amp.Gurney gusunder.

#3

AtomRat
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From: Katazone, VIC
Joined: 22 May 2014
Posts: 4,982
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22 December 2016 05:50 pm

Can you take a photo of them on top of a torch or light source of some sort so we can see the colors and detail a bit better?


Wisdom is knowing how little you know

#4

Prospectinglife
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Joined: 10 June 2016
Posts: 19
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23 December 2016 09:25 am

Yeah sure ill have them up by this afternoon, i was wondering if they would still be sapphires with how big and the way they look. Just look like big blue quarts pebbles to me

#5

Heatho
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From: Sydney, NSW
Joined: 29 April 2013
Posts: 8,693
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23 December 2016 09:34 am

The light will reveal if any are sapphires, to be honest they really don't look like sapphs to me, but still post up a pic with light behind them, could be some common corundum in there.


Minelab GPX 5000, SDC2300, CTX3030, Pro-Find-25, patience, lot's of patience.

#6

Prospectinglife
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Joined: 10 June 2016
Posts: 19
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23 December 2016 10:09 am

Ill have to wait till i finish work to get home and take some with light underneath. I dont understand how they would give a better reading than the clear zircons i have. The first picture is what went really positive on the reader out of about half a bucket full. Most didnt have a reading but these went off.

#7

Lefty
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Joined: 01 May 2014
Posts: 917
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23 December 2016 10:38 am

What is "gem reader" device? I think that tests like relative density (specific gravity) and taking a refractive index with a good refractometer might be more reliable indicators but could you give me the name of this particular unit? I'd like to know what it's testing for (thermal conductivity perhaps?)

It's hard to tell from the photo, some backlighting might give a better idea. Most don't look much like sapphires to me unfortunately. But the small one in the centre of the pile towards the top looks interesting - the colourless but brightly transparent looking one. Could possibly be topaz or colourless zircon.

Anyway, I'm interested to see some backlit pics, hopefully you might just have something worthwhile among them. Cross fingers.

Cheers

#8

Lefty
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Joined: 01 May 2014
Posts: 917
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23 December 2016 10:41 am

I tried googling it but only came up with Steven Universe and the Crystal Gems comic books smile

#9

Heatho
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From: Sydney, NSW
Joined: 29 April 2013
Posts: 8,693
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23 December 2016 10:49 am

Might be one of these things Lefty. I'd actually sooner trust my own eyes for sapphire, as I know you probably would also. smile

http://www.ebay.com/itm/Presidium-PGT-C … 2314699549


Minelab GPX 5000, SDC2300, CTX3030, Pro-Find-25, patience, lot's of patience.

#10

Heatho
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From: Sydney, NSW
Joined: 29 April 2013
Posts: 8,693
Moderator
23 December 2016 10:51 am

Prospectinglife wrote:

The first picture is what went really positive on the reader out of about half a bucket full. Most didnt have a reading but these went off.

They might be common corundum, which will have identical properties to gem corundum (sapphire).


Minelab GPX 5000, SDC2300, CTX3030, Pro-Find-25, patience, lot's of patience.

#11

Lefty
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Joined: 01 May 2014
Posts: 917
Member
23 December 2016 10:58 am

Heatho wrote:

Might be one of these things Lefty. I'd actually sooner trust my own eyes for sapphire, as I know you probably would also. smile

http://www.ebay.com/itm/Presidium-PGT-C … 2314699549

Ah ok, yep that's what it is supposed to do....

It provides a quick and easy way to identify diamonds and separate common colored gemstones from one another based on their thermal conductivity

Anyone here ever used one? I've heard that moissanite will give a similar thermal conductivity reading to diamond.

#12

LoneWolf
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From: Gold Coast , QLD
Joined: 12 April 2016
Posts: 216
Member
23 December 2016 01:26 pm

yikes Price is alright, But the postage is out of this world yikes ..... How can they justify that postage.... I just got some parts for a drone out of the US and they charged me $15.90 for just under half a kilo weight... Air Freight..... Although I don't know much about them, I think some of these devices are a bit of a Con.. roll

LoneWolf......

#13

Lefty
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Joined: 01 May 2014
Posts: 917
Member
23 December 2016 03:26 pm

A professional gemologist on another forum related that a particular top-of-the-range one seemed reasonably accurate, don't know what that brand was nor how much it cost.

Thermal conductivity is real and measurable and different gemstones each have their own ranges. Sapphires have a high thermal conductivity which I noticed when trying to polish one dopped with wax on a ceramic lap. The friction generated heat which doesn't disperse that well through the ceramic lap but is conducted effectively by sapphire. Result: the stone heats up, transfers the heat to the dopping wax which then soften and the stone turns out of alignment on the dop right at the final stage mad I love my ceramic polishing laps and use them for nearly everything but it's only sapphire that I've had that problem with so I dop them with epoxy only.

As long as this device is reasonably accurate at measuring what it's supposed to then I think it could have a place as part of an identification tool kit. I wouldn't rely on it alone - I would want to test any result it gave against other indicators like relative density, refractive index, even a simple scratch test. It's probably really fast to give a result - probably a couple of seconds - and anything that gave a reading would be worth further examination. But yes, an experienced eye is one of the best things.

Prospectinglife, do you have a pointed quartz crystal? You should find it all but impossible to scratch a sapphire with quartz.

#14

rough2cut
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Joined: 11 September 2014
Posts: 147
Member
24 December 2016 12:33 pm

The trick is to have a proven master sample and have evrything on a stainless steel plate so they are all the same temparature when testing and dont handle with hands they transfer heat too.

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