Red zircon VS red Sapphire?

[mangoat]

How do you spot the difference between Sapphire and zircon?

Have been told this is zircon but the clarity is pretty good and the identification was very quick.

Just asking.

 

[user 4386]

Hardness testers are probably the easiest - topaz (8) will scratch zircon (7.5) but not sapphire (9). Sapphire will EASILY scratch zircon.

If you need to do it often:

https://prospectors.com.au/products/moh-scale-hardness-points-1?_pos=1&_sid=4d1c39501&_ss=r

I have never tried the following but they can be as cheap as $10 ex-postage, typically around $25 (they use electrical or thermal conductivity and are non-destructive):

https://www.dmia.net/what-is-a-diamond-tester/

A third method which is very accurate is to use a refractometer. However this requires some learning, and most useful instruments are expensive (most cheap ones cannot measure refractive indexes as high as the gemstones you would be interested in).

Specific gravity is not a sensitive test for those two minerals.

 

[Brumble-Gum]

Try putting it under a UV light. Red sapphire (or ruby) will be fluorescent.
Looks the colour of garnet to me.

 

[Heatho]

That first pic I'd say looks 100% like a sapphire but, the second pic and the colour of it looks very different to any sapphire I've personally seen though they do come in multitudes of colours. Good advice by BG to pop it under a uv light

Could possibly be a padparadscha sapphire, very rare in Aus but they are found here.

 

[user 4386]

Try putting it under a UV light. Red sapphire (or ruby) will be fluorescent.
Looks the colour of garnet to me.

Zircon also fluoresces, but yellow, not the often strong red of ruby. Garnet might not fluoresce, although some do, but not red,

https://www.gemstonemagnetism.com/fluorescene_in_relation_to_magnetism.html

I also wondered if it might be garnet. Hardness is much softer than ruby, and most are slightly softer than zircon (although some are equal).

 

[Heatho]

A refractometer is probably the best way to identify this stone as GR has already mentioned but you'll probably need a trained gemologist to do that.

 

[Pat Hogen]

Does garnet fracture in a conchoidal pattern? I thought it chipped clean along a line.

 

[user 4386]

Does garnet fracture in a conchoidal pattern? I thought it chipped clean along a line.

No. garnet normally has a strongly conchoidal fracture pattern. Ruby has conchoidal. Zircon has conchoidal to uneven. Not a diagnostic feature to separate them.

 

[user 4386]

It should not be too difficult to get hold of a bit of zircon, topaz, corundum (sapphire, ruby) etc and therefore have a good hardness testing kit for these harder stones. Either buying bulk uncut and sharing, or simply having some members make up some cheap kits from their rubbish leftovers.

Sapphire is not hard to get a small bit of around the gemfields and it has the same hardness as ruby, and it will easily scratch zircon and make railway tracks in garnet. Do it under yojur hand lens.

I see so many questions here that could be solved in a minute in the field if people made themselves a hardness testing kit from other mineral fragments. I can understand people not wanting to fork out $185 for a hardness testing kit from prospectors supplies. If you search around you can probably get one much cheaper:

https://www.ebay.com.au/itm/164956736282?hash=item2668300b1a:g:BsQAAOSw3wFgyASR&frcectupt=true

This one would cost $53 including postage to Australia.

https://www.ebay.com.au/itm/181681700383?hash=item2a4d12be1f:g:8BgAAOSwH2ldOBkJ

Remember :
1. Talc
2. Gypsum
3. Calcite
4. Fluorite
5. Apatite
6. Orthoclase
7. Quartz
8. Topaz
9. Corundum, i.e. sapphire, ruby
10.Diamond

1. The
2. Girls
3. Can
4. Flirt?
5. And
6. Other
7. Queer
8. Things
9. Can
10.Do

You could priobably get 8 and 9 in a few minutes in a mineral dealer.