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Tanzanite Substitute


#1

Hi Robert Could you refer me to a book or a chart which gives
descriptions on the hardness and durability of stones that could be
used as substitutes for Tanzanite? I’ve also been wondering WHAT if
anything could replace a Tanzanite if need be…

Yours sincerely
Ethel Sage


#2

Ethel,

 I've also been wondering WHAT if anything could replace a
Tanzanite if need be... 

I definitely would not consider an Irradiated Blue Fluorite in the
place of a Tanzanite in a jewelry piece, like a ring, that could be
subjected to banging against a hard surface. Fluorite is a soft
stone and cleaves easily. It might work in a pendant or earrings -
in a piece that would not be subjected to getting banged or chipped
like a ring.

Another possibility would of course be a blue sapphire - depending
upon the size of the stone you are looking to use - or even a
diffusion treated blue sapphire - these could be good options for
use in a ring.

If price is the reason for looking for a Tanzanite substitute -
there were some really nice looking Tanzanite Simulants at the last
two February Tucson Shows. I am not really sure what the material
was - it may have been a diffusion treated quartz - but the price
was very accessible - $5 - $10/ carat.

Another possibility would be an irradiated Blue Beryl - which would
have the hardness of an aquamarine and come in various shades of
blue all the way up to a deep cobalt sapphire blue. These are what
we call ‘special care’ stones - they should be treated with the same
care as Kunzites as they are heat sensitive and the color could fade
if the piece is left for prolonged periods in direct sunlight, like
in a shop window or on the window sill above the kitchen sink, etc.
These would be available in sizes up to 20 - 25 carats and also in
calibrated sizes. They would be more expensive than the Tanzanite
Simulants or even the Irradiated Blue Flourite but probably less
expensive than the diffusion treated Blue sapphires.

By the way, the last time I bought Tanzanites from a wholesale
dealer, I was required to sign a waiver which stated that I was
aware that Tanzanites should not be placed in a steamer, or
subjected to heat from a torch, or put into an ultrasonic cleaner.
Apparently this dealer had had several stones tried to be returned
because the jeweler did one of these things and the stone shattered
due to the internal stresses that were caused by the heat treatment
to turn the Tanzanite blue from it’s natural brown color.

 Could you refer me to a book or a chart which gives descriptions
on the hardness and durability of stones that could be used as
substitutes for Tanzanite?  

Here are some suggestions for books which give some of the
for which you are asking:

‘Gem Identification Made Easy’, Antoinette L. Matlins, Gemstone
Press, distributed by Van Nostrand Reinhold, NYC - Sometimes
Gemstone Press has a deal where you get some simple Gem
Identification tools along with the book, in a package deal - a
dichroscope, a chelsea Filter and a 10X loupe. Antoinette Matlins is
a very lovely person and she is usually giving seminars at the
Tucson February shows at the AGTA (Convention Center) Show. <
www.gemstonepress.com >

A simpler book, but with a lot of color photographs, and technical
is ‘Gems of the World’, Walter Schumann - my copy is in
Portuguese - so I don’t know the name of the publisher of the
English version

Another one similar to the Walter Schumann book with many fine color
photographs is ‘Precious and Semiprecious Stones’, Jaroslav Bauer &
Vladimir Bouska, Octopus Books

Best regards
Robert Lowe
Lowe Associates - Brasil
Gemstones, Rough, Specimens
Tucson February 6 - 11, 2003 - GJX # 205
e-mail: USA robertplowejr@juno.com
e-mail: Brasil <@Robert_P_Lowe_Jr1>