The World's Most Useful Gem & Jewelry Monthly Newsletter
Written by Carolyn Doyle for customers of The Dorado Company and other visitors to the
azgem.com website who subscribe.
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To enquire about gems or jewelry...
Usable Gems... and a little opinion.
Spinel Gems Are Real
Spinel gems are beautiful, colorful, durable... and
somewhat rare
"Spinel gemstones are all fake. The lady at (discount
superstore) told me so!"
After reading last month's newsletter attesting to the
fact that zircons are real gems, I received this response from a reader
My response to her is... "Real spinel gems are
produced by Mother Nature, just as gem zircons are. Man does produce a
synthetic version of spinel in the laboratory for use in class rings and low
cost jewelry, so the lady at the store probably accurate in describing her
jewelry."
Synthetic spinel is readily identified with a microscope
or by measuring the
refractive index or specific gravity with gem instruments. Also, the chemical
formula is a little different than natural spinel.
Spinel is actually a mineral group called magnesium
aluminum oxides. The spinel family of gems all have similar chemistry and
crystal structure.
Red spinel is historically the most prized color. Many red
spinels were originally identified as rubies. The Black Prince Ruby in the
British crown is a great example.
Spinel gems naturally occur in many other colors as well,
including pink, orange, green, blue, purple, violet, lavender, white
(colorless), and black.
Experts are divided on the question of whether natural
spinel occurs in yellow. I've seen yellowish-green stones, but never a true yellow.
Pure
spinel is colorless. Colors occur when nature allows chromium, cobalt, iron,
zinc, manganese, and/or nickel to substitute for a little of the magnesium or aluminum in the
crystal lattice.
Red spinel gems are colored by chromium, just as rubies
are.
Natural spinel gems are closely related to sapphire and
ruby. (corundum) in chemistry. Corundum is aluminum oxide (no magnesium).
Here is a table showing the similarities of spinel and
corundum.
Characteristic
Spinel
Ruby and
Sapphire
Chemistry
MgAl2O4
Al2O3
Hardness
8
9
Refractive Index
1.718
1.762 – 1.770
Crystal Structure
Cubic
Hexagonal
Specific Gravity
3.63
4.00
Spinel gems are more rare than sapphires and
rubies, but curiously, about one third the price. In my opinion, they are just
as beautiful. I consider all that to be good news.
Because these to gems are so similar, it is not surprising
that they occur together in metamorphosed
impure limestone (marble), and in the gem gravels that result from the
decomposition of the marble.
It
is thought that the spinels crystallize first, using up the available magnesium.
Gems that crystallize after that are corundum because of the lack of magnesium.
Spinel is a name with disputed
origin. Some say the word comes from the Latin word "spina"
(thorn), a reference to the common crystal shape. Others
theorize the name is from the Greek word "spinther"
(spark), a reference to color.
Spinel ruby is an outmoded name
applied to this gem. Other old names include balas ruby. This a
reference to the ancient mining location of Badakhshan,
a region comprising parts of northeastern Afghanistan and
southeastern Tajikistan. Spinel was mined there in
ancient times. about the year 750 AD, and probably
earlier.
Spinel gems were recognized as a
distinct species in 1587 in Burma (now Myanmar), but was not
recognized in other parts of the world for another several
hundred years.
The earliest known use of spinel
for adornment was about 100 BC in a Buddhist tomb in
Afghanistan.
Spinel gems are now mined in
Tanzania, Madagascar, Sri Lanka, Vietnam, Burma, Afghanistan,
and neighboring regions of Central Asia. There are other, less
commercially important deposits in additional locations.
Click on the box...
and have Google start putting money in your bank account!
spinel gems is a keyword search phrase that return a number of
internet listings and ads... but probably none with prices as low as
mine.
Gem Industry News...
Auction Sets New High
For A Rolex Datona
A record price for a Rolex Datona watch was set at a recent
“Important Watches” sale at Sotheby’s in New York City.
The Rolex stainless steel Oyster Cosmograph Daytona sold for
$505,000 to a private bidder (price included buyer's premium).
It was a new record for a Rolex Daytona and the second-highest
price achieved in auction for any Rolex watch.
IA number of Patek Philippe timepieces also sold at high
prices. A gold automatic minute repeater with hinged case went,
for $301,000; a large gold automatic perpetual calendar with
Doré dial and moon-phases, for $400,000 and a platinum
rectangular tourbillon with 10-day power reserve, for $265,000.
“The results demonstrate the strength of the market for
modern watches, particularly Patek Philippe, as well as for
unusual Rolex sports model watches,” said Aaron Rich, head of
the Watches Department in New York. “We saw excellent global
participation with bidders from Europe, Asia and America.”
The Las Vegas Gem
Shows Are Here
The Las Vegas gem shows will begin at the end of May. If
you're going, let us know. We may be able to get together for
coffee...
Jewelry
Dealers
Mother's
Day and graduation
season are right around the
corner... plus, anniversaries and birthdays are always coming up.
All
are good reasons for your customers and their friends to buy
jewelry.
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Are you rewarding your customers with discounts or
freebies when they send you a new customer?
Keep the Make An Offer
program in mind. You can always pick up a few good deals
there.
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spinel family of gems all have similar chemistry and
crystal structure.
Mother's
Day and graduation
season are right around the
corner... plus, anniversaries and birthdays are always coming up.
