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 Post subject: Equivalent in carats in emeralds, rubies, ...
PostPosted: Thu Apr 05, 2018 6:21 am 
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Hi,

I'm searching in Google without results any table or similar to calculate carats of differents gemstones using measurements and cut which they are not diamonds.

For emeralds, rubies, tanzanites, ... where can I find it?

Thank you.


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 Post subject: Re: Equivalent in carats in emeralds, rubies, ...
PostPosted: Thu Apr 05, 2018 12:32 pm 
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Can you estimate the carat weight of a diamond for different length measurements and cuts? If so, then you can convert that result into carat weight for emerald (or ruby): just multiply the diamond result by the SG for emerald (or ruby) and divide by the SG for diamond.

specific gravity of those three materials.
diamond SG = 3.52
emerald SG ~ 2.73
ruby SG = 4

So for the same volume of each material, emerald will weigh less than diamond and ruby will weigh a bit more than diamond.


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 Post subject: Re: Equivalent in carats in emeralds, rubies, ...
PostPosted: Thu Apr 05, 2018 1:13 pm 
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Ok, that's a good idea but it has a problem... SG of diamond can variety inside of a range, I mean it can be 3,49 not 3,52... so everything changes and the same for rubies and emerald and so on, but yes, it's going to happen with tables for that too.

Thank you very much!


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 Post subject: Re: Equivalent in carats in emeralds, rubies, ...
PostPosted: Thu Apr 05, 2018 1:40 pm 
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Ah, but see... any estimate of carat weight using geometry is just that... an estimate. And even that estimate has to assume some value for diamond SG. If you are worried about finding an exact value of carat weight, just pull the stone and weigh it.

Even then, don't expect to get exactly the same weight when the measurement is done in different places, such as a ground floor in Bangkok vs. the twentieth floor of a skyscraper in Manhattan.


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 Post subject: Re: Equivalent in carats in emeralds, rubies, ...
PostPosted: Thu Apr 05, 2018 2:47 pm 
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Try that.
But be careful.
https://gemval.com/weight-calculator.php


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 Post subject: Re: Equivalent in carats in emeralds, rubies, ...
PostPosted: Thu Apr 05, 2018 3:24 pm 
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Okay, I will....

Using gemval calculator for diamond - round shape, I chose length = width = 5.3mm and depth = 5mm to give me something close to 1 ct. Actually the gemval calculator gave 0.96 ct.
Switching to emerald with same measurements, gemval gives 0.74 ct.
Switching to ruby with same measurements, gemval gives 1.10 ct.

Using my own suggestion, if I start with a diamond of 0.96 ct.
...when I convert to emerald, I get 0.74 ct.
...and when I convert to ruby I get 1.09 ct.


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 Post subject: Re: Equivalent in carats in emeralds, rubies, ...
PostPosted: Thu Apr 05, 2018 3:48 pm 
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Brian wrote:
Okay, I will....

Using gemval calculator for diamond - round shape, I chose length = width = 5.3mm and depth = 5mm to give me something close to 1 ct. Actually the gemval calculator gave 0.96 ct.
Switching to emerald with same measurements, gemval gives 0.74 ct.
Switching to ruby with same measurements, gemval gives 1.10 ct.

Using my own suggestion, if I start with a diamond of 0.96 ct.
...when I convert to emerald, I get 0.74 ct.
...and when I convert to ruby I get 1.09 ct.


Oooook, you won hehehe thank you!

And thank you for you Isi


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 Post subject: Re: Equivalent in carats in emeralds, rubies, ...
PostPosted: Fri Apr 06, 2018 8:40 pm 
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https://www.gemselect.com/calibrated-si ... -chart.php


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