Gemology: "Specific Gravity" Liquid???

[Newbie333]

Gemologists... just a question...

RE: "Specific Gravity" Liquid...

A diamond''s Sp.Gravity is 3.52, and so I was told if I bought 3.32 fluid I could identify moissanite because its gravity is 3.21 and would ''float'' in 3.32... where as the 3.52 weight of the diamond would make it ''sink'' in 3.32 fluid...

Is this correct?

Also... what about ''colorless sapphire'' and ''cubic zirconia?''

The sapphire''s S.G. is 4.00 and the CZ is 5.80... These are both heavier than the S.G. of the diamond''s 3.52, and all three would sink in 3.32 liquid... so I''m thinking you''d need a liquid that''s heavier than a diamond''s in order to see the diamond float, but lighter than the C.S. or CZ in order to see them sink, thus knowing in a simple way which is which.

Do they make a S.G.liquid heaver than 3.32? In the Rubin & Son catalog there is a liquid set for sale but doesn''t have anything that''s heavier... it says there is a way to adjust it.

Any help from you guys on this would be greatly appreciated.

Thanks!

-NB333

 

[Garry H (Cut Nut)]

Unless you are experianced in handling dangerous materials and well set up, you should not go near heavy liquids.

I just read your other post, and it seems you may get in over your head NB333.

These liquids are extremely toxic (worse than poisonous) and carcinogenic.

 

[mike04456]

I will agree with Garry 100%. Heavy liquid testing is only for experts. Some of those concoctions are beyond nasty.

 

[oldminer]

If you are thinking about a specific gravity test then you need to have an unset stone. If you do the gemological tests in the correct sequence you probably will never use SG liquids, or rarely use them. You will never need those over 3.32 although they exist.

One can weigh the stone and back up through the weight estimation standard formulas to approximate the SG and close enough is usually sufficient. Since the formulas are not dead accurate, you cannot get the exact SG from them, but they will tell you the correct range of SG and that may be useful in the rare case.

 

[Rank Amateur]

What are those liquids made of that are so heavy and so nasty?

I always thought Karo syrup would do the trick.

 

[dimonbob]

Listen to all the guys above and don't even go there. Heavy liquids are not something even a fair gemologist should play with. I guess the only safe one is salt water that us sometimes used to float amber.
Some of the nasty liquids are:
Clerci Solution
Bromoform
Methylene Iodide
Ethylene Dibromide
Benzene
Toluene
Just to name a few.
I think back when I was teaching at GIA in a closed classroom with 24 students doing SG testing. It is a wonder nobody passed out!

 

[TooMuchInformation]

This is really interesting to know - I have read one book that mentions the use of these chemicals, and doesn't take care to note the actual level of the danger that they pose.

Speaking for myself, it's awesome to see this sort of stuff from real gemologists in the field, because it's a priceless resource for those of us who are learning.