Post subject: Measuring Specific Gravity Without a Hydrostatic Balance
Posted: Thu Jan 31, 2019 9:22 pm
New to the Forum or The Quiet Type
Joined: Thu Nov 16, 2017 11:31 am Posts: 8
Hi all, I came across a webpage that showed how to measure specific gravity without using a hyrdostatic balance and only a small digital scale and a cup of water.
My question is how accurate, if at all, would this method be?
1. Find weight of the stone. (1.98 grams)
2. Zero out the scale and weigh the cup of water by itself, then zero that amount out. (37.18g zeroed to 0g)
3. Dip the stone in the water without touching the bottom or the edges. I use an old guitar string the doesn't measure anything when I dip it in the water alone... (.40g)
4. Divide the weight of the stone by the weight of the submerged stone for the specific gravity. (1.98/.4 = 4.95)
I've come across a number of colored gemstones that read higher than 1.8 on my cheap refractometer, so I'm simply trying to determine cubic zirconia vs zircon if possible.
Post subject: Re: Measuring Specific Gravity Without a Hydrostatic Balance
Posted: Fri Feb 01, 2019 1:52 pm
Site Admin
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
Quote:
Hi all, I came across a webpage that showed how to measure specific gravity without using a hyrdostatic balance and only a small digital scale and a cup of water.
My question is how accurate, if at all, would this method be?
1. Find weight of the stone. (1.98 grams)
2. Zero out the scale and weigh the cup of water by itself, then zero that amount out. (37.18g zeroed to 0g)
3. Dip the stone in the water without touching the bottom or the edges. I use an old guitar string the doesn't measure anything when I dip it in the water alone... (.40g)
4. Divide the weight of the stone by the weight of the submerged stone for the specific gravity. (1.98/.4 = 4.95)
I've come across a number of colored gemstones that read higher than 1.8 on my cheap refractometer, so I'm simply trying to determine cubic zirconia vs zircon if possible.
Thanks in advance for any replies!!!
I'm sure you could test this on your own with some known samples. Try it with quartz, fluorite, synthetic corundum and report back. Good luck!
Sidebar: Cubic Zirconia is a simple separation from zircon.
Zircon is doubly refractive, profoundly doubly refractive when viewed with magnification.
If you have a hand held spectroscope like an OPL, zircon is also easily identifiable.
Post subject: Re: Measuring Specific Gravity Without a Hydrostatic Balance
Posted: Sat Feb 02, 2019 6:55 pm
New to the Forum or The Quiet Type
Joined: Thu Nov 16, 2017 11:31 am Posts: 8
Thanks for the info. I don't have a spectroscope, but I'm thinking of purchasing one...I have trouble with single and double refraction still, need to do more reading...
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