Likely Alexandrite.Remarkable by a color change from Red to Green in
different lighting.Plenty of folks on the list will likely reply with
it’s gemmological stats,so I will limit this reply to lesser known
facts. It was first discoved in Russia,and those rare one found are
still considered the worlds finest example.The name is derived from,I
believe the daugter of a Russian Czar,Alexandra.It is also found,again
very rarely,in Sri Lanka and Africa.In more quantity it can be found
today in the Marambia area of North Minas Gerias,Brazil.Along with
Crysoberyl,in the same variety,a yellow to grayish color,often filled
with silk so that cut in cabachon you have what the trade calls
Precious Cat’s Eye.In Brazil the quality is not up to Russia,they are
often opaque,and transparent top color change Alexandrite and
Crysoberyl can often be found intermingled in the same crystal.The
quantities found in Minas Gerias,although mostly lower grade,were
world record 5 years ago.Even in this production,a gram
stone,transparent and good color change would have been a giant.Most
found are melee size only.But not melee size in the price.The
production has gone to little or nothing in the recent years,as under
pressure from world conservationalists,the Brazilian Government
flooded the area to restrict mining.Look out for the imitations and
synthetics of Alexandrite.Likely the most common ID stone presented to
Gemologists is the synthetic Spinel imitation.These can be
10-20ct,flawless,strong color change and most often found in school
rings and the like.Not believable,yet you will have hundreds of gold
fever infected folks show them to you over your career.More
problematic is the Japanese synthetic.Initially indistinguishable from
the genuine,it caused enough trade uproar that the manufacturer place
a doping agent so they can be seperated.Recently,even reported on
Ganoksin list,is a rash of highly radioactive Crysoberyl on the
market,mostly in the East.It seems some rogue lab in China treated
them with likely electrons(Linier Accelerator),then released them
reactive.My tests on Crysoberyl on low dosage Gamma(Colbolt
60),produced no activity,but no color change either.Point of
interest,the same effect the Chinese achieved can be acomplished
without the radioactivity by long term exposure in Gamma.But the
dosage of a Linier Accerator they likely used,5-20,000 megarads,an
hour or two’s dose, can take even the fastest Colbolt units,a stand up
one,years to duplicate at their one megarad per hour dosage rate and
often intermittent scheduling.Still food for thought for an
entrepreneur or even the Linier process to leave a legacy for his
future descendants.Myself,I have a 1 kilo flawless intense Canary
Yellow Beryl crystal sitting under water for 15 years so far.Some far
off relative 100-150 years from now is going to be quite profitably
pleased. Mark Liccini