Estimating Carats of Cabs

[fernwood]

Going to try to sell, once again, the Sleeping Beauty cabs I made in the 1980's.  
Had an email appraisal done that estimated average value of $4.50/carat for the lot of 25.  Some higher, some lower, depending on matrix and size.  

Previously, I used an online size conversion tool, but the carts seemed a little low.  The conversion tool said that a 10 mm by 7 mm by 2 mm cab would be 1 carat.  Does that seem right?  14 mm by 7 mm by 3 mm was 2 carats.
 
All of these have backing.  I did not include the backing while running the conversion.  Just the size of the turquoise.

I do not have a scale that weighs in grams.   

Any suggestions?  Thank you.   

[rockjunquie]

That's a tough one. First, when I see the weight of a backed turquoise, I just assume that the backing is included in the weight. 2nd, you can multiply carats by 5 to get the gram weight. I would not sell in carats, I would see by the gram. Yes, those estimates seem low to me.

[Don]

The only way to know for sure is to buy a scale that will weigh in carats. Backing is often included in the carat weight, just make sure as much excess backing as possible has been removed. Finished turquoise cabs is frequently sold by ct weight, although I don't know much of it actually sells...

[orrum]

Carat is weight. Go to harbor freight and buy a scsle. It will give you lbs, oz and also grams. Then just convert grams to carats. My advice is to sell with a quarter or something for size reference and not bother with carats or grams. If your turquoise is backed then weight will not be accurately represented. If they are not backed, well all turquoise needs to be backed with Devcon or something otherwise it will crack when a smith goes to mount it. Hope this helps. I question the valuation that you have.

[orrum]

Oops I just saw that yours are backed.

[johnjsgems]

Scales can be bought relatively inexpensively. Look for something with your target weights mid scale (for instance don't buy a 100 lb scale if you will measure only very small items. Most scales lose accuracy at ends of scale.

[rockjunquie]

Scales can be found cheap now a days, but sometimes you get what you paid for. After getting many duds over the years, I finally bought an expensive professional one. When you get one, try to get one with the little weights and tare ability so you can test it frequently. Also, and this is important- If you are not using it for a long period, remove the batteries. Use it on a flat, hard, level  surface with no breeze or fan on it.

eta- tare ability = calibrate.... I had a brain fart.

[gemfeller]

It's considered unethical to sell backed cabochons of any type -- turquoise, opal, etc. -- by weight. They are usually priced by the piece instead due to the extra weight of the backing.

Carat scales are reasonably priced these days and there are some very accurate ones that usually weigh in both carats and grams (5 carats per gram). Most lapidary/jewelry supply houses have a wide assortment of scales for sale. Be aware that not all scales are legal for trade. If you're selling your goods you should have a scale that's approved for trade by the state where the sale is made. It's a law that isn't always enforced strictly but it's a law, and sellers should be aware of.

[fernwood]

Agree about scales. I have worked several places where hardware was sold by weight. Our scales had to be labeled as legal for trade and professionally calibrated twice per year.
Also agree that using a scale to sell by weight would be a problem due to the backing.

So, will figure out a plan B for selling. Might try using my digital calipers to get a more accurate measurement, as I used a ruler before.

Thank you to those who replied. Appreciate it.

[Don]

Aug 16, 2017 13:22:16 GMT -5 gemfeller said:

It's considered unethical to sell backed cabochons of any type -- turquoise, opal, etc. -- by weight. They are usually priced by the piece instead due to the extra weight of the backing.

Carat scales are reasonably priced these days and there are some very accurate ones that usually weigh in both carats and grams (5 carats per gram). Most lapidary/jewelry supply houses have a wide assortment of scales for sale. Be aware that not all scales are legal for trade. If you're selling your goods you should have a scale that's approved for trade by the state where the sale is made. It's a law that isn't always enforced strictly but it's a law, and sellers should be aware of.

That's interesting. I see people selling backed, natural turquoise by the ct weight all the time, both online and in-person. In fact, I rarely see these type of stones offered for sale any other way but by the ct.

[gemfeller]

Don, so do I but that doesn't make it right. I cut opal doublets and I'd never sell them by the carat because I consider it a deceptive trade practice. In the opal world, doublets sell at a big discount from solid stones no matter how great they look face-up. I feel the same way about turquoise or any other backed stone. Otherwise the entire concept of selling gems by the carat is meaningless.

[fossilman1]

What you could do is price the cabochons taking into account the backing. Backing does nothing to add to the value,imho. All you can do is estimate the percentage weight of the backing and price accordingly.

Those weights are really low.

[Deleted]

Aug 16, 2017 9:04:38 GMT -5 rockjunquie said:

That's a tough one. First, when I see the weight of a backed turquoise, I just assume that the backing is included in the weight. 2nd, you can multiply carats by 5 to get the gram weight. I would not sell in carats, I would see by the gram. Yes, those estimates seem low to me.

Ahem... Point of order
One must:
Divide carats by 5 to get gram weight.