DIAMOND SIMULANTS !

I have been recently asked if I can again list what Diamond Simulants are on the market today and how do you tell if you have a simulant or real diamond. The problem is, new ones are appearing at regular intervals and it is very hard to stay current. Well the oldest test, but not totally conclusive is to run the diamond (or rock) across a piece of glass and if it scratches it, it is probably a diamond. As seen on TV you could hit it with a steel hammer ,and if it isn't ruined, it may be a diamond. Yea, but what jeweler or vendor in his or her right mind is going to let you do either of those two tests. So your best bet is to completely trust your gemologist or jeweler that what you are being sold is genuine. And if you bye a diamond from someone you don't know, you probably better make sure you can return it, because if you have it tested and find it is not a diamond, you want some recourse on what you spent. And of course the best saying is, "If it is too cheap for what it is suppose to be, it probably isn't what it is advertised to be!" The following is a chart of some simulants if you want to test for yourself.
.
Common Diamond simulants and their gemological properties
.
Material. Formula..Refractive Index.Dispersion.Moh's Hardness.Density.Thermal.Cond

Diamond......C..................2.417..............0.044...............10................3.52....Excellent

.
Artificial Simulants:
Glass.......Silica...............~ 1.6................> 0.020.............6.............2.4-4.2........Poor

White Sapphire .Al2O3....1.762 ................0.018.............9.................3.97.........Poor
Spinel...MgO·Al2O3.........1.727.................0.020............8................~ 3.6..........Poor
Rutile......TiO2.................2.62 ..................0.33.............~ 6................4.25.........Poor
Strontium Titanate.SrTiO3.2.41................0.19.............5.5...............5.13.........Poor

YAG.......Y3Al5O12.......1.83....................0.028.............8.25...........4.60..........Poor

GGG.... .Gd3Ga5O12..... ..1.97.................0.045.............7................7.02...... ..Poor
CubicZirconia.ZrO2.......~2.2....................~0.06..........~8.3..............~5.7..........Poor Moissanite....SiC..............2.648................0.104...........8.5...............3.2..........High

.
Natural minerals that (when cut) optically resemble white diamonds are rare, because the trace impurities usually present in natural minerals tend to impart color. The earliest simulants of diamond were colorless quartz, topaz and beryl (goshenite); they are all common minerals with above-average hardness (7–8), but all have low RIs and correspondingly low dispersions. Well-formed quartz crystals are sometimes offered as "diamonds," a popular example being the so-called "Herkimer diamond". Topaz's SG (3.50–3.57) also falls within the range of diamond.
.
From a historical perspective, the most notable natural simulant of diamond is Zircon. It is also fairly hard (7.5), but more importantly shows perceptible fire when cut, due to its high dispersion of 0.039. Colorless zircon has been mined in Sri Lanke for over 2,000 years; prior to the advent of modern mineralogy, colorless zircon was thought to be an inferior form of diamond. It was called "Matara diamond" after its source location. It is still encountered as a diamond simulant, but differentiation is easy due to zircon's anisotropy and strong birefringence (0.059). It is also notoriously brittle and often shows wear on the girdle and facet edges. Much less common than colorless zircon is colorless scheelite. Its dispersion (0.026) is also high enough to mimic diamond, but although it is highly lustrous its hardness is much too low (4.5–5.5) to maintain a good polish. It is also anisotropic and fairly dense (SG 5.9–6.1). Synthetic scheelite produced via the Czochralski process is available, but it has never been widely used as a diamond simulant. Due to the scarcity of natural gem-quality scheelite, synthetic scheelite is much more likely to simulate it than diamond. A similar case is the orthorhombic carbonate cerussite, which is so fragile (very brittle with four directions of good cleavage) and soft (hardness 3.5) that it is never seen set in jewelry, and only occasionally seen in gem collections because it is so difficult to cut. Cerussite gems have an adamantine luster, high RI (1.804–2.078), and high dispersion (0.051), making them attractive and valued collector's pieces. Aside from softness, they are easily distinguished by cerussite's high density (SG 6.51) and anisotropy with extreme birefringence (0.271).
.
Desert Diamonds are also known as Saudi Diamonds, or sometimes Qaysumah Diamonds. They are natural, semi-precious stones from the same micro-crystalline family as Amethyst, smoky Topaz and Citrine. These unique, high-grade stones have physical properties that produce the appearance of the expensive carbon-based diamonds! DESERT DIAMONDS are FOREVER, just like their carbon diamonds cousin. They are guaranteed not to discolor or break with age. This is the huge advantage of owning Dessert Diamonds vs. cubic zirconia. Compared with the carbon-based stones, which have a hardness factor of 10 on the Mohs scale, the Desert Diamond are only rated at a mere 7.0 on the Moh's Scale!
.
Due to their rarity fancy-colored diamonds are also imitated, and zircon can serve this purpose too. Applying heat treatment to brown zircon can create several bright colors: these are most commonly sky-blue, golden yellow, and red. Blue zircon is very popular, but it is not necessarily color stable; prolonged exposure to ultraviolet light (including the UV component in sunlight) tends to bleach the stone. Heat treatment also imparts greater brittleness to zircon and characteristic inclusions. Another fragile candidate mineral is Sphaerite (zinc blende). Gem-quality material is usually a strong yellow to honey brown, orange, red, or green; its very high RI (2.37) and dispersion (0.156) make for an extremely lustrous and fiery gem, and it is also isotropic. But here again, its low hardness (2.5–4) and perfect dodecahedral cleavage preclude sphalerite's wide use in jewelry. Two calcium-rich members of the Garnet group fare much better: these are grossularite (usually brownish orange, rarely colorless, yellow, green, or pink) and andradite. The latter is the rarest and most costly of the Garnets, with three of its varieties—topazolite (yellow), melanite (black), and demantoid (green)—sometimes seen in jewelry. Demantoid (literally "diamond-like") especially has been prized as a gemstone since its discovery in the Ural Mountains in 1868; it is a noted feature of antique Russian and Art Nouveau jewelry. Titanite or Sphene is also seen in antique jewelry; it is typically some shade of chartreuse and has a luster, RI (1.885–2.050), and dispersion (0.051) high enough to be mistaken for diamond, yet it is anisotropic (a high birefringence of 0.105–0.135) and soft (hardness 5.5). Discovered in the 1960s, the rich green tsavorite variety of grossular is also very popular. Both grossular and andradite are isotropic and have relatively high RIs (ca. 1.74 and 1.89, respectively) and high dispersions (0.027 and 0.057), with demantoid's exceeding diamond. However, both have a low hardness (6.5–7.5) and invariably possess inclusions atypical of diamond—the byssolite "horsetails" seen in demantoid are one striking example. Furthermore, most are very small, typically under 0.5 carats (100 mg) in weight. Their lusters range from vitreous to subadamantine, to almost metallic in the usually opaque melanite, which has been used to simulate black diamond. Some natural spinel is also a deep black and could serve this same purpose.
.
Because Strontium Titanate and glass are too soft to survive use as a ring stone, they have been used in the construction of composite or doublet Diamond simulants. The two materials are used for the bottom portion (pavilion) of the stone, and in the case of strontium titanate, a much harder material—usually colorless synthetic Spinel or Sapphire—is used for the top half (crown). In glass doublets, the top portion is made of almandine Garnet; it is usually a very thin slice which does not modify the stone's overall body color. There have even been reports of diamond-on-diamond doublets, where a creative entrepreneur has used two small pieces of rough to create one larger stone. In Strontium Titanate and Diamond-based doublets, an epoxy is used to adhere the two halves together. The epoxy may fluoresce under UV light, and there may be residue on the stone's exterior. The garnet top of a glass doublet is physically fused to its base, but in it and the other doublet types there are usually flattened air bubbles seen at the junction of the two halves. A join line is also readily visible whose position is variable; it may be above or below the girdle, sometimes at an angle, but rarely along the girdle itself. The most recent composite simulant involves combining a CZ core with an outer coating of laboratory created amorphous diamond. The concept effectively mimics the structure of a cultured pearl (which combines a core bead with an outer layer of pearl coating), only done for the diamond market.
.
So again, get to know your jeweler or gemologist and don't be fooled by unknown vendors, salespersons and especially eBay and other auction sellers without having a chance to check-out the item completly yourself, with return rights.
.
.

Those Color Change Stones ! Surprise Someone !

Wear the same necklace or earrings in the daytime, or at night, in florescent lighting or incadescent lighting and make people think you have a whole wardrobe of jewelry. Most people that have ever had anything to do with gemstones are aware that certain stones change color under varying light conditions. Many of these color differences are apparent only to the trained eye, but the so-called "color-change" gems exhibit this tendency to such a dramatic degree that it is obvious to even the untrained eye.

.

For most Alexandrite is the everyday example and all know the saying : Emerald by Day - Ruby by Night", greenish under daylight or flourescent light and reddish under incandescent light.

.
Color-change Garnet changes from bronze in daylight to a rose pink under incandescent light.

.
Although most Sapphires have some color change to them and why good Sapphire markets only trade during daylight, the color-change Sapphire exhibits a range of many different color changes. Most color change Sapphires are blue under natural light and purple under incandescent indoor lighting.

.

But there is a fourth color-change stone that in sizes from 5 carats up, exhibits a raspberry red to leaf-green color change as dramatic and complete as that of fine Alexandrite. So why doesn’t this Turkish delight get the respect it deserves? It's true name is Turkish Diaspore. But recently it has been given a new name - Zultanite. This marketing name - Zultanite—a deliberate misspelling of Sultanite which was already the registered trade name for another Turkish product. One would think Turkish-sounding names like Ottomanite or Caliphanite would have done a better job of invoking Turkish history, than substituting a “z” for an “s”? In any case, Zultanite Gems LLC, based in Fort Lauderdale, FL, has been doing its best since 2005 to capture attention for this inexpensive, all-natural rare gem with a hardness between 6 ½ and 7, and minuscule yields of 3 percent from the rough. Maybe the fact that this company has the sole rights to mining of this gem at its only known source, some 4,000 treacherous feet up in the mountains of Anatolia, prevents others from joining the company in the promotion of this gem.

.

So take a look at these pictures above and note that unlike other color change gems that need separate lighting environments to show their color states, this highly pleochroic gem can perform multi-colored wonders when cut with that purpose in mind.

.

One other stone that must be mentioned at this point because of it's popularity is Zandrite. This stone is a type of synthetic glass that was developed by a major glass manufacturer. One of the developing scientists realized that there was a gemstone marketing application possible and started the ball rolling to create a new synethic gemstone sensation. Based on the reaction from the public, he was quite successful. Since Zandrite changes color is the reason for it being named Zandrite ... sort of a cutesy take-off on the name of Alexandrite. It was most likely an effort to fool the unknowing consumer who might mistake the Zandrite name with the Alexandrite name and think they were getting the real thing for pennies on the dollar compared. Zandrite is a man-made lab created stone that was specifically produced to mimic Alexandrite, an imitation not a synthetic, but in many settings is a beautiful gemstone in its own right. This mimicing went over so well, that there are now other color-changes available in Zandrite gems.

. .

.

And not to be left out, is the Russian Lab-created Alexanderite. Synthetic lab grown (created) Chrysoberyl Alexandrite gems many times exceed natural Alexandrites in clarity and color change, and since they are 'real' Alexandrites grown from seed stones, confuse even some of the best gemologists and jewelers. Synthetic lab grown gemstones are like comparing a rose grown outside to one grown in a greenhouse, both are the real thing - BUT ! Also be cautious when buying lab-created Alexandrite, because many dealers indiscriminately use the term imitations and are making reference to color-change Corundum, which Alexandrite is a member of the family, instead of stating it is synthetic Alexandrite. A fine line but a distinction that should be made and disclosed to customers.

.

Additional Info --- I have been informed I left out color-change Tourmaline. I was unable to find any reference to such, but do remember hearing about it the Tucson Gem Fair. I do not have one or have I ever seen one. If anyone can provide a picture showing both colors I would definitely appreciate it.

.
Thanks to the ISG, Zultanite Gems LLC and others for information and pictures of color-change gemstones.
.

The Trapiche Gemstones !

Everyone should always keep their eye open for some of the neatest and fairly rare gemstones in existance --- the Trapiche Gemstones ! The Spanish word trapiche was used in Colombia with a literal translation that means 'wagon wheel'.

.
It was and still is applied to a rare form of Emerald that has inclusions aligned along the edges where the crystal faces meet, which causes the stone to literally look like a wagon wheel. The most famous and best known is the 'Trapiche Emerald'.
.

A Trapiche Emerald, found only in Colombia at Coscuez, La Peña in the celebrated Muzo mining district
.
But......the trapiche 'wagon wheel' formations can indeed occur in other types of gemstones, i.e. Ruby, Sapphire, Tourmaline and particularly in a form of Andalusite. So the term 'Trapiche' must be clarified by adding the name of the Gemstone along with it.
.

For insatnce Trapiche Ruby, of which there are two distinct types, one with the carbon 'wheel' from Viet Nam and the second with the lighter colored 'Calcite' or 'Dolomite' wheel' from the Mong Hsu region of Myanmar (Burma).
.

A Trapiche Sapphire, probably of Burmese origin.
.

A Trapiche Tourmaline, of this green variety, can be obtained from the Kavungu mine in the vicinity of Jivunda southeast of Mwinilunga in northwestern Zambia.
.

A Trapiche Andalusite, called Chiastolite, has the same kind carbon spokes as the Emerald and Ruby. This particular form of Chiastolite is found in areas around Georgetown, California. It is also known to many as "The Cross Stone" in religious circles.

.
And I have been told there is a Trapiche Garnet, but have never seen one or even a picture of one, so definitely something to look for.

.

Pictures from own collection and those of some close friends. The locations indicated are where these particular speciems originated from.

.

.

North Carolina's "Emeralds" !

After several years of legislative debate, the North Carolina Legislature finally in 1973, settled on the Emerald as the Official State Gemstone. This selection was made hard by the fact that North Carolina is host to more than sixty-three different types of naturally occurring gemstones and minerals! Many of these are very rare, including Emerald, Aquamarine, Sapphire, Garnet, Topaz, Amethyst, Citrine, Rutile, and Tourmaline, along with an abundance of world class smoky and clear Quartz crystals. In addition, North Carolina is famous as the only place on earth where the very rare gemstone "Hiddenite" can be found!

.

Nestled snugly in the foothills of the beautiful Brushy Mountains of North Carolina is located the small town of Hiddenite. This locality is recognized as one of the most unique and interesting geological locations on the North American continent. Each year, thousands of rockhounds, tourists and educational field trip participants flock to this popular North Carolina attraction to experience the thrill of finding rare gemstones in the rough. Whether a serious or amateur prospector hoping to fulfill dreams of finding hidden treasures, a student experiencing an enriching "hands on" learning experience or a family seeking quality outdoor recreation, they can all be found in this area.

.

Another very popular area is in the mine fields around Franklin, in Macon County, in the western tip of the state. No matter which direction you arrive from, you'll pass through some of the prettiest areas of the Blue Ridge Mountains. Waterfalls, rock-clustered streams of rushing water, scenic mountain views, something for everyone. This area is especially noted for its Corrundum finds. Sapphires and Rubies are both variations of corundum. We tend to think of Sapphires as blue, but they can be green, pink, yellow, and many other colors depending on the presence of different impurities. All colors of Corundum are called Sapphire except one: Red Corundum is always a Ruby. A few mines in the area produce the rare Star Rubies and Sapphires, stones that produce a six-pointed star when they're cut into a cabochon shape, with a smooth, rounded, dome-like top. The star is the result of needle-like inclusions that react with light.

.

Depending on who one talks with or which advertisement is read, there are between 30 to 50 gemstone producing mines in North Carolina, with only a small handful working commercially these days. Some mine have been in continuous use since the 1870s.

.

Again, don't confuse the Emerald as being the State Gemstone with the State Rock named in 1979, which is Granite. Although Granite is found all over the State, the most famous location is Chimney Rock State Park which is located just 25 miles southeast of Ashville.

.

.

Montana's "YOGO" Sapphires

Sapphires are the official Montana state gem and have shared this honor with Montana Agates since 1969, but one type of Sapphire in particular stands out: the Yogo Sapphire. The Roberts Yogo Mine in central Montana is the only commercial Yogo Sapphire mine in the world, and a new group is helping to ensure that the process of getting the gems from the mine to the store is done responsibly. Mike Roberts, the new owner of Roberts Yogo Company, explained why he came to Montana from Alaska, where he mined for gold: "Just a new adventure to see, sounded like something fun to do, and hopefully there would be lots worth doing, (and) lots of money in it."

.
All it takes is following what Roberts calls the "yellow brick road," so named because limestone rock has a vein or dike running through it. The "road" runs hundreds of feet underground. And about every 30 feet of any given vein, there are 10 carats of sapphires, considered by many to some of the best in the world. But contrary to common belief, striking it rich isn't just a matter of luck. Roberts said: "None of it's luck. It's just the more dirt you move, the more sapphires you get." In just a couple of years, they have already found some 100,000 carats. The underground ore, ladened with sapphires, is loaded up and taken back to the surface. It's then sorted and the water washes away the ore. Yogos are considered more valuable because they are natural and untreated, unlike other sapphires, but they tend to be small. And after being mined, they get cut and shipped to stores, and that process is the focus of a group called the Earth Solutions Committee. The group includes Roberts, area jewelers, gem cutters and environmentalists.

.
"The idea of conscionable mining is something that reaches across sectors," explained Committee representative Claire Baiz. "We are going to add value to the Yogo sapphire by demonstrating that it's socially responsible and environmentally ethical in the way we mine and cut and distribute and sell the Yogo sapphire." The mine does not use chemicals and even outside observers seem impressed. Stuart Levit of the Center For Science In Public Participation said, "As mining goes, (it's) probably as clean as you can ask for. However, ‘how clean' is clean is always a real big question." This is just one of the questions this group will try to answer in the effort to make the Yogo sapphire even more precious.

.

History of the YOGO Sapphire started in the late 1880s, Yogo City was like a ghost town. The hundreds of people who had come to the town looking for gold had deserted it. Only a few people remained. Yogo City had been one of the least productive areas for gold mining in all of Montana. It was not until 1895 when Jake Hoover came to Yogo City looking for gold. Like many of the miners, he noticed the tiny blue pebbles that settled down to the bottom of the gravel bed along with the gold. But unlike others, he saved the pebbles. At the end of the season, he sent a box full of these little blue pebbles to New York for expert evaluation. The box was eventually examined by gemologist Dr. George F. Kunz, who identified the little blue pebbles as a rare untreated sapphire.
.
From stories presented on KRTV and KPAX.
.
Added comment from e-mail received: Other Sapphires found in Western Montana (known as "Montana Sapphires") do not have the YOGO's cornflower blue color and brilliance and usually are heat-treated to attain their blue color ...so don't be confused. Yogo sapphires are different from any other sapphire found on the globe. Also, other colors of Sapphires that are commonly seen in jewelry stores are not found in Montana.

.