Message-Id: <8Xf1T7y00jWEI2hHIF@andrew.cmu.edu>
Date: Sun, 18 Dec 88 15:40:39 -0500 (EST)
From: Frank Ritter <fr07+@andrew.cmu.edu>
To: bovik@cs.cmu.edu
Subject: diamonds

I enjoyed reading your previously saved messages on diamonds.  Here
are my results to add to your files:

I looked at about 10 stores and 25 diamonds in Pittsburgh, Boston, and
Amsterdam and I liked the following stores:

DAVE WEISS:  people there don't know anything, and sometimes their
rocks are overpriced, sometimes underpriced.  I got mine on sale
there.  They use a distorted scale, offereding generally more flawed
stones, but with good color.  It's good to bring your own loupe, for
they only have a plastic one.

THE JEWELRY BUILDING downtown: as previously mentioned in your files.
I liked the two recommended, and found them both courteous, and
helpful.

FORBES JEWELRY on Forbes in Squirel Hill: I had my diamond appraised by the guy
(owner) there because his prices were good for a small shop, he knew
what he was doing, and seemed honest.

IMPERIAL JEWELRY: in Squirel hill also on Forbes, Jack the owner
seemed less than honest.  A lot of people out ot buy a diamond have
money in their fist, and will learn exclusively about diamonds from the 
jewler who sells them the stone.  I suspect that alot of $ is made
off of such people -- people who just want "a diamond for my honey",
and Jack should do well.  His prices were insane, so either he is
great, or can afford to sell much much lower than I could find.
Prices to low to be true...that didn't stay as low as I learned more
and checked back with him.

I also toured a diamond cutting factory/showroom in Amsterdam, the
diamond cutting center for the world!  (so called).  The several
places I looked did not offer any outstanding values with the value
of the dollar this summer.  Diamonds are not subject to import
duties, however, it offered numerous other potential problems such as
lose while travelling, and switched merchandise.

REGRESSION 

I did a little regression on the prices I found, and came up with the
following equation:  

price (in $1k units) = color * .07 + size^2 * faults * .00504   
 color is 1 - 10 with D (clear) = 10, M (yellowish) = 1
 size is in deka-points (1/10 caret or 10 points)
 faults is from F (flawless) 10 to SI2 = 3 to I1 = 2 stepping 1 pt /
    GIA division

so a G color (7), .5 caret (5.0), VS2 (5) stone would be $1.12K,
excluding a ring, which can be had for $50 to $200.


The regression does not necc. fit all types of stones, and was
weighted somewhat to reflect my personal taste and expectations.  I
checked the stones I saw against it, and when one came along that
was grossly underpriced, e.g. 50%, I bought it.  The appraisal
confirmed the underpricing...