January 24 Through February 4—TUCSON, ARIZONA: Annual show
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 Post subject: Re: Dr. Hanneman's Tips: 2 :Specific Gravity Balance
PostPosted: Tue Nov 01, 2016 7:16 pm 
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Hello every one,

I realize that the Hanneman specific gravity balance is very nice, cheap and direct to evaluate the specific gravity of a gem. I am interested in that device.

I also read that a lot of gemmologist use digital scale, which is expensive.

I wondered why nobody talked about the old way to evaluate the weight of gem, like this one: http://www.ebay.com/itm/Diamond-Balance ... Swal5YF-fi

All his working life, my father used a tiny balance like that. It seemed to suit his need.

We could use a little glass of water to evaluate the specific gravity? I suppose, it is not a good idea since no one talked about that possibility?


Brigitte


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 Post subject: Re: Dr. Hanneman's Tips: 2 :Specific Gravity Balance
PostPosted: Tue Nov 01, 2016 7:27 pm 
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I don't see how that could work, Brigitte. Maybe I'm just not visualizing it properly.


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 Post subject: Re: Dr. Hanneman's Tips: 2 :Specific Gravity Balance
PostPosted: Tue Nov 01, 2016 7:39 pm 
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Hello Barbra,

Suppose that you weight a gem by placing it on the left. You evaluate the weight on the other side in carat with the little things provided for that.

After, you take off the gem and you put the left side in a little glass filled with water. You place back the gem on the left, in the water. You weight the gem again with the same little things.

After your put your numbers in the equations for the SG. You take the weight en carat in air and you divide it by the difference in your 2 results in carat.

What do you think?

Brigitte


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 Post subject: Re: Dr. Hanneman's Tips: 2 :Specific Gravity Balance
PostPosted: Wed Nov 02, 2016 7:25 am 
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If you put one side of your empty balance in water, it won't be balanced anymore.


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 Post subject: Re: Dr. Hanneman's Tips: 2 :Specific Gravity Balance
PostPosted: Wed Nov 02, 2016 8:14 am 
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Hi Brigitte, look at my "Drawings for specific gravity balance" in "Gem Equipment". Yes, it uses a digital balance, but they are getting cheaper by the month! I bought a certified one to 0.0005 carat for just over $40.00 last year.


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 Post subject: Re: Dr. Hanneman's Tips: 2 :Specific Gravity Balance
PostPosted: Wed Nov 02, 2016 9:55 am 
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Hello Isi and Alan,

Isi, that is a good point. It seems that we can use 2 pans. Look here on the Gemology Project: http://www.gemologyproject.com/wiki/ind ... ic_Balance.

Maybe the little vintage balance is not precise enough? We can weight at the 0.01 carat.

Alan, thank you for sharing. Interesting and helpful, indeed. The chart temperature/precision is helpful also. I wonder where you found a so precise balance at that price. Is the shipping included in that price? I suppose it is in USA dollars.


Brigitte


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 Post subject: Re: Dr. Hanneman's Tips: 2 :Specific Gravity Balance
PostPosted: Wed Nov 02, 2016 11:38 am 
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I think the device will be complicated to build with a two pan balance.
Furthermore, as is written in the link :

"The two-pan scales are the most time-consuming scales to use though some jewelry stores still have them. But they are rarely used for determining SG of stones, mostly because the counterweights are generally too big to be of any help. Besides, they really need to be calibrated every few years."

All in all, for more precision and easiness you had better use a digital scale.


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 Post subject: Re: Dr. Hanneman's Tips: 2 :Specific Gravity Balance
PostPosted: Wed Nov 02, 2016 12:53 pm 
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Sorry Brigitte, a slip of the decimal point, my balance reads to 0.005 carats, or 1 milligram. A two pan balance can be used, by having a bridge and basket over one pan, but as ISI says, single pan is easier.


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 Post subject: Re: Dr. Hanneman's Tips: 2 :Specific Gravity Balance
PostPosted: Wed Nov 02, 2016 5:42 pm 
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Hello Isi and Frank,

Thank you for your answers. Good points, indeed.

Brigitte


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 Post subject: Re: Dr. Hanneman's Tips: 2 :Specific Gravity Balance
PostPosted: Tue Nov 22, 2016 10:39 pm 
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Hello,

Alan: Are you still happy with your new scale? Is it accurate?

If it is accurate, can you tell me where you bought it, please?

I would appreciate.


Brigitte


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 Post subject: Re: Dr. Hanneman's Tips: 2 :Specific Gravity Balance
PostPosted: Wed Nov 23, 2016 5:23 am 
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Hi Brigitte, yes, the balance is performing well, not only accurate, but repeatable and it holds its zero. I bought it from Kern, a crack German instrument firm (Google them). At the time it was very reasonable, but the pound was up against the euro and we have the benefit of no duties in Europe. At the moment the dollar is way down against the Euro and US duties can be eyewatering, so check before ordering.


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 Post subject: Re: Dr. Hanneman's Tips: 2 :Specific Gravity Balance
PostPosted: Mon Dec 05, 2016 3:45 pm 
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Brigitte wrote:
Hello every one,
I realize that the Hanneman specific gravity balance is very nice, cheap and direct to evaluate the specific gravity of a gem. I am interested in that device.
Brigitte

Then, why don't you get one?


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 Post subject: Re: Dr. Hanneman's Tips: 2 :Specific Gravity Balance
PostPosted: Mon Dec 05, 2016 4:40 pm 
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Good day Mister Hanneman,

Glad to hear from you.

I was not able to pursue my interest in gemmolgy for some years, because of health issues. I can not work anymore.

I have been able to go back a bit to gemmology for the last months. I have only the capacity to read a bit about it. Not more.

But I have a lot of fun and pleasure to read on this forum. I am really glad to have the privilege to be part of your group.

Thank you to all of you.

Best regards.

Brigitte


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 Post subject: Re: Dr. Hanneman's Tips: 2 :Specific Gravity Balance
PostPosted: Sun Jan 28, 2018 12:31 am 
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Location: Wylie Texas but in Alaska for a while
Bill Hanneman wrote:
Hold on for just a minute. [-X :smt026

That article was written 50 years ago.

Next month, at Tucson, I will be introducing a new approach to density.
It is based on relative density, which is simpler, faster, and anyone can make themselves in a few minutes.

Keep you eyes open.
I just have to write the instrutions and I have only 10 days. :(



Did this ever get posted?

I know that we are in the middle of this years show, so everyone is to busy...


It sounded like this was presented at the show.

Are there any videos or copies available of these types of presentations?


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