Garnet

We have talked about garnet before. The thing that surprises most people is that garnet can come in virtually any color, except blue, and that is arguable. Demantoid garnet is a rare and expensive green stone, originally from Russia, but also found in Africa, Pakistan and Mexico. Tsavorite is a rich green garnet from East Africa that rivals emerald in color.

Recently there are more color-change garnets coming out of Nigeria (I believe). These stones change from blue to reddish, depending on the light source. Incandescent light has more red so the stones show red. Fluorescent or daylight has more blue color so the gem transmits the blue to your eye. This is very neat, and not cheap at $2,000/carat for a fine one.

Sir Arthur Conan Doyle wrote a fictitious story called “The Blue Carbuncle.” This priceless gem was an impossible blue garnet! Well the color change stones are a recent find… a true blue colored garnet has yet to be found.

Gem Treatments Through The Ages

The ancient Greeks, Indians and Roman’s all have written about different techniques they used to either improve the look of a gem or outright fake a gem. Remember, “anything of value will be counterfeited”. The use of furnaces to heat stones like chalcedony to a better red color was wide-spread. There are recipes for bleaching and polishing pearls (feed them to a goose or rooster). Black onyx was made by soaking stones in a sugar solution then carbonizing the sugar with acid and heat. Most of these early techniques took one stone and dyed it to look like another. Taking a quartz crystal, heating it and shoving it into a green dye causes the stone to fracture; where the stone fractures the green dye is sucked into the new vacuum and into the fractures. This results a green piece of quartz that was then sold as emerald (this technique is called “Quench Crackled”). Many of the treatments were just methods to back a stone with silver-foil or foil of other colors. Modern sapphires and rubies have mostly been heat-treated to improve the color and clarity.

In the 1950’s Australian universities began experimenting with high-heat and very controlled oxygenating or reducing environments in order to lighten the generally over-dark blue Australian sapphires. The Thai heat-treaters learned from these studies and just ran with them. The Thais made a fortune by buying a “worthless” white opaque sapphire called “Geuda” from Ceylon, then heating it to very fine blue colors when they got back to Thailand. Most of the ruby on the market is Burmese heat-treated. In the early 1990’s a new mine was found in Burma; Mong Hsu (it means new mine). The rubies from this source came out of the ground with a blue core and needed to be heated to drive off the blue and leave them a pure red color. Tanzanite needs to be heated to turn it from a khaki-green to the violet we expect. When any gem can be proven to have no treatment it will command a premium; in rubies, for instance this can easily be double the price of a heated stone. No matter what the treatment (or “enhancement”) the ethics are clear. According to the Federal Trade Commission, if the treatment has added significantly to the value of the gem, or is impermanent, it must be disclosed to the consumer.

Topaz

Topaz is the birthstone for November. What color is topaz anyway? Most people will call a dark brown variety of quartz “Smokey Topaz”. In the trade we call this a misnomer. Dark brown quartz should be called “Smokey Quartz”. Quartz and topaz are completely separate gems; with different chemical composition, crystal shape and physical properties. Quartz has a Moh’s harness of 7, while topaz has a hardness of 8. The Moh’s hardness scale relates to a gems scratch-ability. Diamond is # 10 and talc is #1. The higher number can scratch the lower number, but not vice-versa, so topaz is harder than quartz.

Topaz comes in many colors; yellow, pink, blue, green and colorless. The name “Imperial” topaz refers to a rare type that has a hint of pink, often called sherry-colored. In fact pure pink could also be called Imperial topaz. Any pink component to the color is considered very desirable and adds value to the gem.

Blue topaz, as seen in most jewelry stores, is almost always artificially colored by irradiation, starting out colorless. There is natural blue topaz; in fact the Texas state gem is blue topaz, but it usually is a very light blue, like a pale aquamarine.

Some experts say they can feel the difference between topaz and other gems with their fingers. Topaz has a “slippery” feel; other gems won’t let your finger slide across the surface as easily as topaz does. I have tried this and like to think it is true, but I wouldn’t rely on it as an identification tool.

Topaz can come in large sizes. Don’t expect to see many imperfections in topaz as it tends to crystallize very cleanly; so it shouldn’t show inclusions (imperfections) to the naked eye.

Citrine: November’s Alternate Birthstone

Citrine quartz is often used as a substitute birthstone for topaz. Citrine is less expensive and has a similar yellowish color. Quartz comes in a variety of colors: purple, yellow, colorless, brown and rose. Some rare amethyst can be heated and will turn a light green color. Most “green amethyst” in the stores these days is artificially irradiated colorless quartz; not the rarer heated natural amethyst.

The name “Citrine” comes from French “Citroën”, or lemon; for the yellow color. Citrine comes in various shades from brownish yellow to reddish-yellow. Again, when a touch of red is present the gem becomes more valuable. A reddish-orange color is often referred to as “Madeira” colored. In fact, yellow quartz is quite rare in nature. Most citrine is actually heat-treated amethyst which turns from purple to yellow.

An unusual natural combination of citrine and amethyst called “Ametrine” is mined in Bolivia. It comes out of the ground with part yellow and part purple. While very unusual these gems still sell for slightly less than the king of the quartz family which is amethyst.

Scammers Are Back

Gold prices are falling slowly and the stock market is jumping all over the place; reminds me of the late 1970’s and early 1980’s. Another thing that is reminiscent is the appearance of scam artists selling diamonds as investments. Be very careful of this ploy; it cost so many so much back in the 1980’s.
Basically, the pitch is that you can buy “certified” diamonds that are worth much more than you are buying them for (red flag), or that the diamonds will jump in price and net you a tidy profit when you sell them. The main question is “Where will you sell them?” Jewelers buy at wholesale and /or often get diamonds from diamond dealers on loan; without having to pay for them until after they sell. Jewelers are not a good choice to sell to, unless you want to get less than wholesale value.
These investment companies say they will buy back the diamonds at any time, but in the past that was the problem. They didn’t buy the diamonds back, or they were out of business when the time came to sell them.
The gent who came in asked me what his investment diamonds were worth (last week). He had paid $11,000.00 for three fancy yellow diamonds that had a wholesale value of around $4,000.00. He had wired the money to the company, but wasn’t worried, as he had 10 days to return them…I wish him good luck.
Reputable jewelers remember the bad-old-days of investment scams for diamonds and other gems. Everyone was crazy for diamonds and the prices went higher than ever; higher than they are now, 30 yeas later. Diamond dealers at that time were borrowing from banks to buy more diamonds, and using the new diamonds as collateral to buy even more diamonds. Companies were buying diamonds as investments for retirement funds. Eventually it just all fell apart. In 1982 the price of diamonds fell by half.
It has been a very long time since I have seen this type of scam. It used to be an almost exclusively Canadian phenomenon; Canadian investment scammers selling to clients in the USA from boiler-room phone operations. People would come into stores where I worked with gems sealed in plastic boxes, with certificates and instructions not to break the seal. Inevitably the gems were of very low quality and worth next to nothing, or a fraction of what was paid.
While diamonds, and other gems, will generally “hold their value” over generations they are not considered an “Investment”; which implies a profit will be realized on resale. The only real way gems are an investment is if you own a jewelry store, buy wholesale and sell retail.
Not to imply that gems are not worth having. Aunt Trudy’s 5.00 carat diamond will have considerable value; even after 80-100 years. Most other things we own will have been used-up and worn-out; with no value, after that amount of time.

What Are Chocolate and Black Diamonds Anyway?

One of the latest trends in diamond jewelry is the use of black and chocolate diamonds, set with white diamonds for contrast. Diamonds come in every color you can think of. When they are other than brown or yellow they are automatically called “Fancy” and are generally very expensive. If they are dark enough (past a specific tone) then browns and yellows will also be called fancy. Different chemicals and structural anomalies cause the color in diamonds. Traces of nitrogen cause yellow, boron and hydrogen cause blue, green is caused by natural irradiation in the earth. Structural deformation on an atomic level cause brown and pink colors by changing the way light travels through the diamond.

Black diamonds are colored by an abundance of black inclusions: if you look at them in a microscope you will see a speckled reflective surface and areas of transparency mixed with black opaque areas.
Brown diamonds are called by many appealing names; basically you can make up whatever name you like; champagne, chocolate, cognac, whisky, cinnamon, sherry… knock yourself out! Generally the name will reference a depth and shade of color.

Pink Diamond Smashes Auction Record Price

Sotheby’s auction house sold a large pink diamond recently; for almost double the amount previously spent on a diamond. The pink emerald-cut weighed 24.78 carat and sold for $46.18 million dollars in the November 2010 auction. It was graded as Fancy Intense Pink. The last time this diamond was seen was when the famous New York jeweler Harry Winston last sold the ring 60 years ago to an unnamed client. The new owner is Laurence Graff, a famous London jeweler; he has named the diamond the “Graff Diamond”.

Ethiopian Opal

People who have seen the new opal from Ethiopia, called Welo, have varying opinions on it. Everyone agrees that it looks fantastic, but what we need to know is whether it is stable, or will it crack from dehydrating over time? Turns out that dealers who are selling it swear by it, and dealers who don’t have any to sell say they wouldn’t trust the stuff.

What are we to believe? With the gem business sometimes it is better to wait a little while and see what happens. In time, if these opals prove to be stable, they will change the face of world opal business forever. Or…they will prove to be too fragile and will be forgotten about. Chances are if they do turn out to be unstable someone will discover a technique to stabilize them artificially. It always happens that if a deposit of gems is unsalable, then along comes a gem treater to fix them up and make them pretty.

As long as everyone is told what has been done its OK. If any treatments are done, but not disclosed, then it is fraud.

Big Time Auctions are Going Nuts

International auctions are going gang-busters. According to Sotheby’s auction house their jewelry buyer spent an average of $275,000.00 last year as opposed to $80,000.00 in 1995 (wow!). The average sales price of a piece of jewelry with Sotheby’s in 2010 was $93,000.00 (Geeez!). The buyers are shifting from traditional buyers in the jewelry trade to private buyers in emerging economies. Asian buyers were 20% of all buyers and accounted for 30% of sales in the last two years.

One 28.78 carat Fancy Intense Pink emerald-cut diamond, with VVS2 clarity, sold for a mere $46.16 Million dollars: a record price for any jewel ever sold at auction.

Used Gold and Diamonds are Selling

People are selling their diamonds back to jewelers and pawn shops. This practice has almost tripled in the last five years because of economic upheavals, and the high precious metal prices. The estimated quantity of diamonds sold in 2010 ranged between 2 and 3 million carats, or about the same amount that a respectable diamond mine might produce in that time. Between 1976 and 1999 more than 400 million pieces of diamond jewelry were sold back to the jewelry trade by the public.

Peridot

This month’s birthstone is Peridot.  Peridot is a sort of bottle-green to grass-green colored gem; colored by Iron.  In the ancient days it was known as topaz, a name taken from the island Topazios in the Red Sea off Egypt. The island was often hidden by fog and sailors had a difficult time locating it. The island today is known as St. John’s Island.  This was the only ancient source of peridot.  They say the discovery of peridot on the island was made by pirates, but that the location was then lost for centuries, only rediscovered in the 1900’s.

Peridot has a hardness of 6.5 and consequently will wear more than a harder gem such as sapphire or ruby.  If you look with magnification, the back facets will appear doubled; as peridot has strong double refraction.  Double refraction is the effect produced by some stones where a beam of light is split into two beams within the stone; so the back facets appear as two lines rather than one line.

Burma (Myanmar) produces some of the finest peridot in the world.  In order for the color of peridot to really look intense, the gems need to be of a somewhat large and rare size, over 10 carats.  In this size, in a fine quality, they can rival emerald in intensity of color.  Arizona and Mexico produce much of the available peridot, but it is almost always below 3 carats finished weight.

Interestingly, peridot forms in some stony-iron pallasite meteorites.  These are thought to have formed in a destroyed planet at around the time our solar system came into existence (4.5 billion years ago).  They consist of crystals of peridot (olivine to a mineralogist) embedded in an iron-nickel core.  They think they formed at the boundary of a planet’s iron-nickel core and the silica-rich mantle and were “liberated” by a catastrophic collision of another planet or asteroid.

Watch Where You Shop

Every month we get to see items of jewelry not sold by us.  People come in for a second opinion; as they for some reason doubt the word of whomever they purchased from.  One nice lady had an alexandrite she had purchased from E-Bay.  Luckily she only paid for what she got; which was a slice of natural sapphire glued onto a base of synthetic alexandrite.  Tricky really; at first glance through the microscope a person sees natural inclusions in the sapphire slice.  Without turning the stone sideways, the deception might not be discovered.  She said she would report the vendor.

Another pleasant woman had purchased a pair of diamond earrings at a tourist town in Colorado.  The diamonds were half the size they told her they were, and of a substantially lower quality.  The jewelers will refund her money, but are charging her a “restocking” fee.  She has a receipt stating the promised, but incorrect, information.  If she had the time and inclination, she could take the jeweler to court and demand replacement with what they told her she was buying.  Interestingly (and not surprisingly) the jewelers discounted the price from $1,200.00 to $450.00 almost immediately when she first was looking at them.  Regardless of price; it is never acceptable to misrepresent the size and/or quality of gems.  When you buy jewelry make sure the weights and qualities of the diamonds, or other gems, are clearly written on your receipt, and/oryou receive a replacement value document (appraisal) that details that information.

Remember that the little plastic “Certificates” that some stores show next to their diamonds are usually just a sales gimmick.  Often the grading is “soft” (easy); the diamond is described as better than it may actually be.  If the card shows a “Retail Value” that is much higher than what the diamond it is actually selling for, then the “Retail” value is really a “Fake” value.  Things should appraise for, and be valued at,  close to what they  will actually sell for.  The oldest trick in the book is to over-mark the price of an item so you can pretend to discount it.

Make sure you ask about the return policy.  Most reputable jewelry stores have one. Barnes Jewelry, for instance, offers a thirty day return policy for unworn (non special-order or custom- made) items.  If a piece of jewelry doesn’t make you happy we don’t want you to have it, plain and simple.