AZGem Gems

April 2015


gem stone and jewelry newslettergem stone and jewelry newsletter


The World's Most Useful
Gem & Jewelry Monthly Newsletter

Written by Carolyn Doyle for customers of
The Dorado Company

and other visitors to the website who subscribe.




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Usable Gems... and a little opinion.


Precious or Semi-Precious Gemstones



Precious or semi-precious gemstones? It is a question I continue to receive on occasion. People usually ask about tanzanite, precious topaz, or pearls.

Precious or semi-precious gemstones... the designation seems to be of concern for those searching for "precious" birthstones for certain months. These folks express an opinion such as "I should have a precious gem for a birthstone, not just a common gem".



Rare Black Opal



National Ass’n of Jewelers - 1912

Updated American List - 2015

Updated British List - 2015










bloodstone or aquamarine

aquamarine or bloodstone

aquamarine or bloodstone




diamond or rock crystal




emerald or chrysoprase


pearl or moonstone

pearl or, moonstone or alexandrite

pearl or moonstone




ruby or carnelian


sardonyx or peridot


peridot or sardonyx




sapphire or, lapis lazuli


opal or tourmaline

opal or tourmaline




topaz or citrine

topaz or citrine


turquoise or lapis lazuli

turquoise or zircon or tanzanite

tanzanite or turquoise


The standard American list of birthstones was adopted in 1912 by the National Association of Jewelers, a jewelry trade association. Then the Jewelry Industry Council of America updated the list in 1952 by...

    • Elevating aquamarine to be the primary birthstone for March and lowering bloodstone to the alternative position for that month
    • Adding alexandrite to June and citrine to November
    • Choosing a specific color of tourmaline for October (pink)
    • Dropping lapis lazuli from December, and replacing it with zircon

The American Gem Trade Association added tanzanite as the primary December birthstone in 2002.

The British National Association of Goldsmiths adopted a standard list in 1937. This list has also been updated over the intervening years.



Which one is ruby and which is spinel?


It is generally accepted that the Ancient Greeks were the first to designate certain gems as "precious", including ruby, sapphire, emerald, pearl, and opal. Topaz seems to have been included in this category at times.

Semi-precious gems encompassed all of the other known mineral crystals - and organics such as ivory, coral, and amber. Some rocks were also included, such as onyx, bloodstone, jasper, and lapis lazuli.

Precious or semi-precious gemstones were identified at that time...

    • Primarily by color
    • To some degree, by crystal shape
    • And to some degree, by "heft"

Using these simple criteria, the Ancient Greks were able to distinguish garnet from other red gems, and aquamarine, emerald and other beryl gems from heavier gems.



Which one is sapphire and which is spinel?


Using these rudimentary criteria also led to many individual gems being misidentified, especially when confronted with water worn crystals recovered from the same gravel beds.

Spinels and corundum often are recovered from the same gravels, and can exhibit similar colors to the human eye. The ruby and red spinel images, and the blue sapphire and blue spinel images above bear witness to this fact.

Today we have the means and knowledge to positively identify gemstones scientifically. Refractivity, color spectral analysis, and other tests produce highly reliable identifications.



Precious gems were designated as such by the Ancient Greeks because of their rarity (we now surmise). Rarity led to desirability, and to greater value being placed on these stones.

In the intervening centuries many misidentified gemstones have been found to be entirely different species and/or varieties. Many new gemstones have also been discovered, including morganite, tanzanite, and tsavorite.



So now there are many rare, desirable, and costly gems known to exist. Golden beryl is a beautiful gem, as are other varieties of beryl, such as aquamarine and emerald. But golden beryl, although it is somewhat rare, is not nearly as costly as emerald. The same applies to garnet. tsavorite, and other green garnets are costly, as are the color change garnets. spessartite and rhodolite are moderately priced, while almandine is inexpensive.

Precious or semi-precious gemstones... has become an outmoded model for classifying gems. As you can see, the old criteria of rare and expensive can cut across the spectrum of gems available today.

As prices for tourmaline, aquamarine, spinel, and some other gem types continue to increase, they to are "precious" in the eyes of many.



Precious or semi-precious gemstones can also include diamonds. White diamonds are near the top of the list of costly gems. Natural fancy colored diamonds are even more costly. However, black diamonds are relatively inexpensive.

In recent years, technical processes have been developed to manipulate the color of some diamonds. The results can be spectacular. Electric blues and greens, brilliant yellows, and a few other colors can be permanently induced in certain diamonds.

One technical process is known as diamond electron bombardment and annealing. A friend in the diamond business tells me that in this process …

“High energy electron bombardment particles physically alter the diamond's crystal lattice, knocking carbon atoms out of place and producing color centers. Then the electron bombardment treatment is followed by an annealing process. Annealing increases the mobility of individual carbon atoms, allowing some of the lattice defects created during bombardment to be corrected.”

“The final color depends on the temperature and length of annealing, and the diamond's chemical composition. This treatment results in a permanent new color.”

As of this writing, color manipulated diamonds sell for less than naturally occurring fancy colored diamonds. They often sell for less than white diamonds.

While on the subject of color, I should mention color phenomena gemstones. Gems that change color depending on the type of light in which they are viewed. Color phenomena stones sell at a premium.

Precious or semi-precious gemstones is no longer a relevant question in the gem and jewelry industries. Gems sell themselves based on beauty, desirability, and suitability for use in jewelry or in a collection.


gem newsletters


Photo Information


Top - No, it's not emerald, it's chrome diopside from Russia

Next - Rare black opal from the new discovery in Welo, Ethopia

Next - Ruby

Next - Red spinel

Next - Blue spinel

Next - Sapphire

Next - Pink topaz

Next -  Golden beryl

Next - Fancy yellow diamond

Next: - Gem special offer - Electric blue diamond

Next - Industry News - New Gems Special Offers page image

Next - Dealer Product Image - Amethyst Ring in Sterling Silver

Last - Dealer Program Image - Pink Spinel and Sterling Silver Earrings



$1.99/Mo. for 12 months of Economy Hosting at


A Google search for links or images using keywords such as natural gemstones definition or color enhanced diamonds can return some very interesting information and websites.




Gem Offer



Here is this month's special gem deal. 


Gem:     Diamond... the April birthstone

Color:     Electric blue, brilliant color manipulated diamond

Quality:     VS quality gem

Shape:     Round, this stone would make a great ear stud or accent gem

Dimensions:     3.3 mm

Approximate Weight:     .015 carats

Price:     $218, plus shipping ($5)

Send me an email (with anti-spam) (carolynatazgemdotcom) and tell me that you want this fine gem.

We have other  shapes, sizes, and shades of gems available.

We keep gem prices low by buying quality gemstone rough worldwide, and having the rough material cut by our gem cutters in Asia.


gem newsletters


Gem Industry News


More Gem Special Offers


New Gems Special Offers page image


Over the past several months, I have been asked to expand our special offer program.

Specifically, customers show a preference for gems in sizes suitable for ring and pendant center stones, and for pairs of gems for earrings.

While I cannot afford to offer our entire inventory at less-than-wholesale, I will increase the variety and number of gem special offers. Beginning this month I will send a mid-month Gems Special Offers email to our newsletter subscribers and gem dealers.

As usual, each gem will be sold to the first person to send me an email saying they want a specific gem.




gemstone news


Jewelry Dealers



Now is the time to rebuild your inventory

From a supply perspective, now is the time to replenish your depleted inventory. If you have some money to invest in inventory - there are deals to be had. And you should have some cash. After all, that depleted inventory resulted from sales.

From a sales perspective, gift giving occasions have not disappeared. Easter, birthdays, anniversaries, and many other reasons to give nice jewelry at a great price just keep on coming. Your customers (and their friends) need what you offer!

Be The Quality Jewelry Discounter.



gemstone news


Jewelry Dealers Program


jewelry dealers program


Do you enjoy jewelry and gems?

Do you enjoy talking with friends and friends of friends?

Could you use an extra income source?

Take a look at our great Jewelry Dealers Program.



Carolyn Doyle

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