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Demantoid Garnet


#1

I would like to hear peoples opinion of demantoid garnet. I have a
client that came to me wanignone and I am afraid I know very liitle
about the species.


#2

Hi Bob, Demantioid is a chrome green andradite garnet, unusually
brilliant for th e garnet family, normally of Russian origin. Found
in smaller sizes. It really is a beautiful stone. Once again, try
New Era, your best bet to find one reasonably. Best wishes,
Sharon


#3

I find them not as nice as other green garnets. The small size and
horsetail inclusions really are a limiting factor. I have seen nice
bright large light green Mali garnets that were the same shade and I
would even consider light tsavorite (which is far more economical than
Demantoid).

Alicia Miller


#4

Bob:

Demantoid is a very lovely stone, but I’m not sure you’ll easily find
any. Production of the mines in Russia ceased years ago. I have
heard that they had started back up since the fall of the USSR, but I
have not run across any stones.

Even low quality demantoid is likely to be $300 a carat. Extra Fine
stones over a carat appraise over $3000/ct. The characteristic color
is slightly yellowish green. Over 3 carat stones are rare. Typical
"horsetail" inclusions of bytonite are diagnostic. The RI of 1.888
makes for a brilliant stone and the hardness of 6.5 to 7 is fairly
durable.

If demantoid is hard to find, you might try to interest her in
tsavorite garnet. Less than half the price, and very pretty shades
of green and bluish green. Tsavorite from Africa is much more
available.

HTH, Roy


#5

Hi, Bob-

Demantoid garnets are fairly uncommon, and I believe that most which
are commercially available are from the San Carlos Apache Reservation,
the same place that produces much of the world’s peridot, and some of
the finest fire agate (slaughter mountain.)

Demantoids are a gold-green color, sort of like a pale, yellowish
peridot. What makes them stand out is the refractive index, which is
fairly high, and which makes these stones really sparkle.

If you are interested in purchasing demantoids, I believe that they
can be had at a reasonable price from the company listed below:

Blackstar Trading Company Flagstaff, AZ 86001 (520) 526-2671

I’m no gemologist, and I’m sure that other contributors can shed more
light on this stone from a technical vantage. I will say that I’ve
seen cut demantoids, and they are some Pretty Rocks, which is enough
for me…

Lee Einer


#6

dear Bob

Demantoid is a variety of Andradite, which belongs to the garnet
group UgGrandite( Uvarovit,Grossular,Andradite) The name Demantoid is
actually derived from my own dutch language: Demant , meaning diamond
, because of its high dispersion. Demantoid was discovered in 1868 in
the Ural mountains. It was the first type of green garnet discovered.

Chemistry: Demantoid is a Calcium Iron Silicate trace elements:
Titanium,Chromium, Vanadium, and aluminium , in isomorphous
replacement. The colouration depends on the iron content : ferric: Fe2
O3

Refractive index: 1.880 to 1.883 Density : 3.80 to 3.88 gr/cm3
Hardness: 6,5 Dispersion: 0.057 (diamond : 0.044! ) Absorption specrtum
is quit distinctive: strong absorption band at 443 nm cutoff, two
additional bands at 622,640 nm and doublet at 693 and 701 nm .

I hope i have been of some assistance to you !
greetings, wilma van der giessen