Diamonds & sizes

Jewelry Discussion
1

What mm size, roughly would a 1 pt diamond be?
What about a 2 pt or a 4 pt?
Is there a formula or a list on line that someone can recommend?

Thanks,
Amery

2

I created the following PDF a couple of years ago. If you print it
out on both sides of the same A4 sheet you get 4 handy A5 crib
sheets.

Regards, Gary Wooding

3

I have a card which has the approximate weights and sizes marked on
it. According to the card,

a 1pt diamond would be about 1.3mm
a 2pt diamond would be about 1.7mm
a 4pt diamond would be about 2.2mm

Helen Hill
UK

4

Amery,

Please do a Google search with the following words - diamond mm
carats. The search will throw up a lot of links that will give you
diamond weights vs diameters. For instance, when I did a search with
these words, the first few links were as follows:

http://www.walshbrothers.co.uk/Update/dia04.htm

and so on…

Regards,

Rasesh.
Mumbai, India.

5

I think you’ll find that charts may not be completely accurate in
their opinion of MM vs CT. I see charts that state a 2.0mm diamond
is .03ct, but often when I’m billed that 2.0 weighs a bit more.

If one uses the charts for estimating costs its not a bad idea to add
a point or two on melees. It may not sound like much of a discrepancy
but suppose you’re estimating your cost for 35 2.0mm diamonds and
suppose the price is $800 p/ct. If they weigh .03 each your tw is
1.05ct or $840. Should they weigh .035 each your weight is now better
than 1.22ct or $980. By the time you keystone it the difference
becomes $280.

I don’t know about anyone else but I don’t like eating $280 just
because of faulty estimating based on taking someone else’s word.
That’s the trouble with written anything, it becomes accepted as
fact when in truth it may or may not be. And its pretty embarrassing
to ask your client for more money because you made a mistake.

On the flip side, if you order by carat, “Sam I need some three
pointers” You might get 1.9mm or you might get 2.0mm. Again doesn’t
sound like much but depending on the setting (in the aforementioned
35 stone suite) the total length difference becomes 3.5mm. That
could spoil your day.

Usually when I’m plotting out a design I do it by MM requirements.
But I will estimate costs a little higher than theoretical, give a
retail price and stick to it.

6 
I think you'll find that charts may not be completely accurate in
their opinion of MM vs CT. I see charts that state a 2.0mm diamond
is .03ct, but often when I'm billed that 2.0 weighs a bit more.

The chart I mentioned (http://www.ganoksin.com/ftp/GemWeights.pdf )
shows a 2mm brilliant as.035ct, but all such charts are really
intended for estimating.

Regards, Gary Wooding

7 
I don't know about anyone else but I don't like eating $280 just
because of faulty estimating based on taking someone else's word.

This is a common mistake - telling a customer that a piece will be a
flat price because of estimating diamond weight. I buy diamonds by
weight, I sell them by weight. I tell the customer the price will be
$1500/ct and they pay for what they get - if it’s more, it’s more,
if it’s less, it’s less, and I still get mine. Just lately I saved
someone $150 that they could use because the listed weight was that
much higher than what the diamonds actually were. He was a young man
on a smallish budget, and it was much appreciated by him. It’s the
only fair way for custom pieces. Shops who are doing 100 pieces
might sell by TW, and it evens out in the end. Special order they
pay for what they get.

8 
Usually when I'm plotting out a design I do it by MM requirements.
But I will estimate costs a little higher than theoretical, give a
retail price and stick to it.

Thanks everyone for your help on this. yes, I am going to only use
the charts as a guide.

I’m adding gold to my line as well as some small flush set diamonds.
But, after talking to a few diamond dealers on the phone about what
point size to get my head was spinning- there was a huge range. Of
course, I could order by mm size, but I wanted a guide to see how
much I would be spending on each stone (roughly) if I bought a
carat.

That would make a difference in what size I was ordering.

I just wanted to be more prepared, so thanks everyone, now I feel
like I can fake it a little better!

I will be using black and champagne diamonds at first, until my
designs get a little finer. Plus, I really dig them. So, they won’t
be as expensive as clean white diamonds.

Thanks again, everyone!
Amery

Amery Carriere Designs
Romantic Jewelry with an Edge
www.amerycarriere.com

9 
But, after talking to a few diamond dealers on the phone about
what point size to get my head was spinning- there was a huge
range. Of course, I could order by mm size, but I wanted a guide to
see how much I would be spending on each stone (roughly) if I
bought a carat.

Just so you know - I have a chart of mm sizes of diamonds on the
wall, which I only use occasionally because I know much of it by
heart. Using it doesn’t make you unusual or uninformed, it makes you
typical. “How many stones of a size/ct.?, We have a 3mm space so
what weight is going to fit?, What’s the weight going to be for a
space of 2mm wide by 12mm long?, We have a 3ct. diamond so how many
mm is that going to fill?” On and on - use it all the time…