Grams, Oz, Troy Oz, PW, Carets & Scales, oh MY!

Jewelry Discussion
1

I just finished a gem purchase where I had to again borrow a friends
caret scale to see what I was buying and how much it was going to
cost me. It’s time to purchase my own scale.

I went to my trusty tool catalogs and realized I have hit one of
those holes in my knowledge. The scales I was looking at measured:
grams, ounces, troy ounces, pennyweights, carets. While I realize
that all these are units weight, I don’t really know when they are
used & for what.

Does anyone mind giving me a primer on these different weight units?

I do know:

carets are for gems
and
karets is for gold (gawd I hope this is right!)

But I’d like to know the rest.

Thanks so much.
Carla

Related Pages
MetalCalc - Collection of unit’s conversion calculators.
http://www.ganoksin.com/MetalCalc/

2

Here is a site that gives all weight and mass conversions:
http://www.onlineconversion.com/weight_all.htm

The base site will lead you to tables to convert other attributes.

Karat is not a unit of weight or mass but a “unit” signifying
concentration of precious metal with 100% = to 24 see:

jesse

3 
   I do know: carets are for gems

It’s spelled carat, with an “a”, and it IS for gems. It’s also
standard metric, with five carats per gram, so a carat is 200
milligrams.

   and karets is for gold (gawd I hope this is right!)

Again, two "a"s, as in karat. and yes, it’s gold. It is NOT a unit
of weight, however, but a sort of percentage, expressed not as 100ths
(percentage), but as 24ths.

For the others:

Grams are universal metric measurements, used for many things,
including sometimes metal. More by craftspeople than sellers of raw
metal, who use troy ounces. 1000 grams equals a kilogram, etc, etc.
The gram weight unit can be useful with small scales by dieters and
diabetics calculating calories or grams of carbohydrate, and by drug
dealers selling things they shouldn’t.

Ounces, or ounces avoirdupois is the standard english ounce used in
common commerce. It converts to metric as, if I recall it right,
28.8 grams. This is the unit you find on cartons and cans in the
grocery store in the U.S. Sixteen avoir. ounces equals a standard
pound, which is a very small lightweight little unit of measure,
which is why there are so goddam many of them indicated when I step
on the bathroom scale. it’s not that I’m overweight, its that pounds
are so light. right?

Troy ounces is confusing in that it also is an ounce, but this ounce
converts to metric at 31.1 grams per ounce. It’s only use is in the
weighing of precious metals. A troy pound is even more confusing
since it’s only 12 troy ounces, not the 16 we’d have in standard
english ounces and poinds. A troy ounce breaks down to 20
pennyweight, and a pennyweight breaks down to 24 grains. Most of the
time, one uses only ounces and pennyweights (dwt), pounds and grains
are less commonly used.

Some scales also measure pearl weights, yet another unrelated unit
of measure, labeled in the unlikely unit of mommes, which itself
breaks down, if I remember it right, into grains. unsure about that
part though. (I can look it up if you wish). It may be that pearl
grains are troy weight, not some fraction of mommes. The coolest part
of “mommes” for me is that some pearl dealers I’ve known prominantly
pronounce the final “e”, making it sound like they’re weighing
pearls in units named after their mommy. Always brings a slight grin.
Don’t know why. Might actually be the correct pronounciation even.
Again, I don’t know if that’s the case…

Hope that helps.
Peter Rowe

4

Let’s throw volume into this mess! ;^}

How much, by volume is an oz of silver?
Inquiring minds want to know…

Reev

5

Hello About convertions there is a free beauty tool for your computer
(Mass, Temperatrue, Distance, Etc.)
Convert for Windows – joshmadison.com its realy useful. Hope you
enjoy it.

Aurelio

6 
   How much, by volume is an oz of silver? Inquiring minds want to
know...

Get out your calculators kiddies.

An ounce (troy) is 31.1 grams. So a troy ounce of water, which has an
S.G. of 1, would be 31.1 cubic centimeters (cc). But sterling silver,
with an S.G. of, what, 9.5? (Oh go look it up. I’m not getting out of
this chair to verify that for you (grin) but it’s somewhere near
that), would then be 9.5 times as dense, and take up a smaller volume
inversely proportional to that density. To get the volume occupied by
an ounce of a certain metal, or material, take the weight in grams
(in this case, 31.1), and divide it by the S.G. (specific gravity,
which is the proper term for it’s density) of the metal or material.

Peter

7

Well, let’s see- the density of silver is 10.5 g/cc, while there
are 28.375 grams in an ounce, so how many cc’s in an ounce of silver
is 28.375/10.5= 2.702 cc/oz

Hope you find this helpful- Betsy

8 
  " Well, let's see- the density of silver is  10.5  g/cc, while
there are 28.375 grams in an ounce, so how many cc's in an ounce of
silver is 28.375/10.5= 2.702 cc/oz"

Since silver is ordinarily weighed in ounces troy, there are 31.1
g, per oz., not 28.375.

Jerry in Kodiak

9 
   Well, let's see- the density of silver is  10.5  g/cc, while
there are 28.375 grams in an ounce, so how many cc's in an ounce of
silver is 28.375/10.5= 2.702 cc/oz

That works for avoirdupois ounces. But precious metals are weighed
in troy ounces, which contain 31.1 grams per ounce…

Cunfusing stuff. Sure would be nice if the whole precious metals
industry just switched to metric, and we bought metals by the gram,
leaving the whole silly troy ounce system to the history books.

Peter