July 2019 Newsletter: Electric Blue Zircon

Natural Zircon, like spinel, is one of those gemstones which is highly regarded by gem dealers and collectors, but is not well known in the commercial jewelry market. Indeed, some people are liable to confuse it with cubic zirconia, a cheap synthetic diamond simulant.
As a gemstone, Zircon is noted for its high refractive index and outstanding fire. In fact Zircon has a higher refractive index than sapphire, ruby, spinel or tanzanite. Zircon also has impressive fire, with a dispersion rating nearly as high as diamond. Zircon is found in a range of colors, including blue, red/orange, honey and white. High quality zircon makes gorgeous jewelry.
Blue is the by far the most popular Zircon color and fine Blue Zircon has an electric color and more sparkle than any other blue stone in the gemstone world. The Zircon blues range from light to medium to medium-dark blue, sometimes with a slight greenish secondary hue. Blue Zircon is produced by low temperature heating, but only the Cambodian and Burmese zircon will turn blue when heated. Prices depend on color saturation, clarity and size.
7.57 ct Blue Zircon and Diamond Pendant
In addition to its obvious beauty, Zircon has some unusual properties. For example, it has very pronounced birefringence or double refractivity, where the difference between the two refractive indices is unusually high. This can be observed with the naked eye when you look down through the table of a cut Zircon: you will observe facet doubling that makes the facet edges looked blurred. Zircon is also a remarkably dense mineral, with a density about 50% higher than diamond. Only a few minerals such as hematite and cuprite haver a higher density.
Gemologically, Zircon is a zirconium silicate by chemical composition, with a hardness of 7.5 on the Mohs scale. It is suitable for all kinds of jewelry, though protective settings are recommended for rings.
The traditional sources for Zircon are Sri Lanka, Burma and Cambodia. These days most of the fine Blue Zircon comes from Ratanakiri in northeast Cambodia.
Compared to sapphire or spinel, Zircon is still very affordable, and high quality specimens can be found in larger sizes as well. Since Zircon is such a dense material, it is always a good idea to check the size as well as the carat weight when buying Zircon.



Notable Gems from the AJS Collection

This month we feature some of the finest Blue Zircons from our collection, in a wide range of shapes and sizes. Click on any photo to view the details for the gem.

14.29 ct Blue Zircon from Cambodia
14.29 ct Blue Zircon from Cambodia  [SOLD]
An outstanding example of the finest Blue Zircon from Cambodia in a very large size. Top color, completely clean and beautifully cut to bring out the full brilliance of this fine material. This will make a stunning ring or pendant. Guaranteed natural.

7.57 ct Blue Zircon and Diamond Pendant

A gorgeous 7.57 ct deep Blue Zircon set in an 18k white gold pendant with 18 white diamonds with total weight of 1.75 carats. The diamonds include 8 marquises (total weight 1.20 carats) and 8 rounds (total weight 0.32 carats) with 2 diamonds on the bale (total weight 0.23 carats).

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4.15 ct Blue Zircon from Cambodia

A very fine Blue Zircon from Cambodia in a vivid medium blue. This is very clean material that has been expertly cut in a square cushion for maximum brilliance. This beautiful Zircon shows full fire across the face, a really sparkly gem. Guaranteed natural.

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12.52 ct Matched Pair of Blue Zircons from Cambodia

An outstanding matched pair of fine deep Blue Zircons from Cambodia! Very clean and well matched, these have wonderful sparkle and will make a gorgeous pair of earrings for someone special. Guaranteed natural.

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4.48 ct Blue Zircon from Cambodia

A bright medium Blue Zircon in a hard-to-find emerald cut. This is beautifully clean material that has been cut with large facets to show off the vivid color. This fine Zircon will set up beautifully in your jewelery design. Guaranteed natural.

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7.53 ct Blue Zircon from Cambodia

A very fine saturated Blue Zircon with excellent fire. Clean and well-cut, this beautiful gem will surely sparkle in your jewelry design. Guaranteed natural by AJS Gems, Bangkok.

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News from AJS and the Gems World

Ruby is the Birthstone for July

2.03 ct Burma Ruby and Diamond Pendant

If you were lucky to be born in July, your birthstone is Ruby, the queen of colored gemstones. Red is one of the rarest colors in gemstones, and a pure red, like the famed pigeon's blood Burma Ruby, is coveted by connoisseurs.

Fine ruby is so valuable because of its extreme rarity. Ruby is the red color of corundum, the same mineral as sapphire. But where other corundum colors such as blue, yellow and pink are indeed rare, gem quality corundum is extremely rare and is found in only a few locations in the world, most notably Burma.

While fine Burma Rubies continue to be the most valuable in the world, Ruby production from Burma has declined significantly in recent years and most of the larger Rubies entering the market are now from other sources, particularly Tanzania, Mozambique and Madagascar. Mozambique has become particularly important since 2009 when high quality Rubies were found in Montepuez in the northern part of the country. Vietnam has also produced some beautiful Star Rubies.

Fine Rubies have proven to be excellent investments over the years, and this classic gem is a perennial favorite for special occasion jewelry.

See our collection of Fine Rubies from Burma, Mozambique and Madagascar


Ask the Gem Experts

Each month we answer questions from our customers. We welcome your questions and you can submit a question from our contact page.

I loved that Star Sapphire ring in your newsletter. How long does it take to have a ring made? (I would like to surprise my wife for our anniversary) GH, USA

Once we have a design, we can fabricate a custom ring to your specifications in as little as two weeks (some complex designs might take a little longer). We do high quality work using only the finest materials. You can see examples of some of the designs we've done in our Jewelry Gallery. We look forward to working with you on your project, and we guarantee you'll be delighted with the results!


I saw some Morganite gems advertised as "Pink Emerald". Is that its new name in the gemstone trade? MT, UK

Both Emerald and Morganite are members of the beryl family of minerals (along with Aquamarine, Goshenite, Red Beryl and Yellow Beryl). But in the gem trade the name Emerald refers specifically to the chrome green color beryl. The term pink emerald would generally be regarded as misleading. Morganite is a beautiful gemstone in its own right and should be referred to as Morganite or Pink Beryl.


All the best in gems,

Ron, May & and Rung