"Responsible Gold?"

There is a lot of current press regarding what is known as "Responsible Gold." This is a term coined to describe ecologically friendly mining techniques. The truth of the matter is that precious metal mining has historically been destructive to the enviornment. One only has to travel to the former gold fields in California to see the still denuded cliffs which were blasted with streams of water in order to remove gold bearing rock. 70% of the gold mined in the world goes into the fabrication of finished jewelry.
Nevada is currently the leading producer of gold in the USA. The primary occurence is called the Carlin Trend. It is located west of the city of Elko in Northern Nevada. Dangerous elements such as Mercury, Arsenic, and CYANIDE are used to extract microscopic gold from the earth. The days of finding large nuggets or "easy pickings," are long gone.With the current spot price of gold at over $600.00\ounce previously uneconomical deposits are being reworked. While metallurgical engineering may provide ecologically friendly technology for mining someday, it has not done so yet. None of us want to see what is left of the earth destroyed in the pursuit of greedy corporate profits. WAIT! The shareholders in these multi-national mining corporations are in the way! Not to worry. The enviornmentalists have already won their case in the court of public opinion.

Gem Identification (Part 7) Microscopy

Does this instrument look familiar? No need for an introduction here! Stereoscopic binocular microscopes are a very useful investment in gem identification. And, they reveal a LOT of interesting features in diamonds and colored stones. Unlike a loupe, it's relatively handsfree to use. The range on this scope is from the standard 10x magnification to 120 power. When the magnification is increased the field of view decreases and illumination has to be increased. Microscopic examination of the unknown red cabochon reveals "silk," which is characteristic of corundum. Corumdum is the "family" name for rubies and sapphires. Since this "cab" has shown all of the correct parameters for the red variety of corundum, it is what it is. A natural untreated ruby cabochon. Gem identification doesn't necessarily include all of the tests that have been shown here. Some tests such as polariscopy and refractometry are mandatory in most cases. Some identifications require spectroscopy to seperate natural from synthetic or laboratory created gems. If you think this kind of work is "fun" you are correct. I am always looking at new gemstones. And, guess what? No two are ever exactly alike in every respect. Talk about variety!

Gem Identification (Part 6) Spectroscopy

Spectroscopes are used to seperate white light into its component colors. (Remember Sir Isaac Newton and his invention of the prism?) Various chemical elements or CHROMOPHORES are coloring agents in gemstones. The absorbtion lines or bands in the spectroscope indicates the elemental coloring agent in many circumstances. This instrument is often needed to distinguish dyed from natural colored Jadeite jade. Also, color treated diamonds can be detected. The unknown red cabochon shows absorbtion in the red portion of the spectrum indicating Chromium as the chromophore. I think I have enough information to make a definitive identification at this point as Chromium is the key to this stone.

Gem Identification (Part 5) Dichroscopy

This is a very useful instrument called a Dichroscope. Some doubly refractive gemstones display what is known as Pleochroism (gr. many colors). For instance, the unknown red cabochon show red and orange colors when the tube is rotated. The examination is conducted under cool diffused light.

Gem Identification (Part 4) Refractometry

This is called a Refractometer. It measures a ratio called the Refractive Index. The Refractive Index indicates the speed of light in the air divided by the speed of light inside the gemstone. When light enters a gemstone 2 things happen. The light is refracted or bent, and the light DECREASES in speed. The Refractometer measures the bending of light inside the gemstone and converts it to a numerical value. The range is 1.31-1.81 as viewed though the lens. The technique involves placing the gemstone upside or table down over a minute drop of contact liquid which is extracted from the brown bottle. This test is sometimes VERY CONCLUSIVE as in the case of Tanzanite which has a somewhat unique R.I. that is not seen in other stones. This instrument also indicates OPTICAL CHARACTER as the lens is rotated during examination. The unknown red cabochon shows a R.I. of 1.76-1.78

Gem Identification (Part 3) Polariscopy

This is a gemological instrument called a polariscope. The gemstone is placed between the two lenses and illuminated. Depending upon what is seen through the top lens the OPTICAL CHARACTER of the unknown gemstone can be determined. This is a very important factor as gemstones are either singly refractive (isotrophic) or doubly refractive (anisotrophic). In this case, the unknown red cabochon shows a doubly refractive response.

Gem Identification (Part 2)

Once a gemstone has been examined under 10x magnification it is measured and weighed. The stone being weighed here is a unknown red cabochon. Cabochons are not faceted like other gemstones. In Nevada all scales used for commerce MUST be certified. The yellow sticker was affixed to this scale after a state inspector tested it for accuracy. This is a portable Dendritics scale with a capacity for weighing up to 100 carats at a time. The unknown red cabochon weighs 11.09 carats. It is highly included and appears to be a "hard" gemstone given its polish and vitreous (glass-like) luster.

Gem Identification (Part I)

Everyday gem identification work begins with a sorting pad, stone tongs, millimeter gauge, and a 10x power magnifier commonly known as a loupe (pronounced loop). Loupes come in different magnifications and apertures. The standard for gem identification and diamond grading is 10 times magnification. I prefer loupes with large apertures as they allow a greater amount of light to enter the lens. The lens is actually composed of 3 glass lens cemented together called a triplet lens. The loupe is CORRECTED for what is known as spherical and chromatic aberration. To the trained eye many gemstones can be identified at first sight under this level of magnification. Gemstones that are not conclusively identified at first sight then undergo a series of non-destructive optical tests that render identity a certainty. It is basically a process of elimination.

Steam Cleaning

After jewelry has been cleaned in the ultrasonic machine the final touch is steam cleaning. It serves to remove any lingering traces of residue and dries the item. HANG ON! The steamer uses a p.s.i. of 70. As in 70 pounds per square inch of vapor. So, I use special long tipped rubber tongs to secure the item under the blast of steam. Don't try this at home! LOL! A little goes a long way!

Ultrasonic Jewelry Cleaning

This is a Gesswein ultrasonic cleaner. It incorporates a heating switch along with an automatic timer. The vat contains a specially formulated cleaning solution which becomes VERY hot thus shortening the cleaning time. The process of ultrasonic cleaning is known scientifically as "cavitation." X number of solution molecules actually implode on all surfaces loosening polishing residue and other substances which cling to polished goods. BEWARE! This is an aggressive cleaning process which has to be done carefully. Set stones which are not set securely in their mountings have a tendency to come loose and fall to the bottom of the tank. It is part of the cleaning protocol to FIRST identify the gemstones that are set. Diamonds clean quite well. BUT, certain gem materials such as Emeralds, Opals, Pearls, Amber, Turqouise, and especially Tanzanite should NEVER be cleaned by the ultrasonic method. They are prone to damage not only by the cavitation process but also by the thermal shock of the VERY hot solution. This is why you should find a store with qualified gemologists on staff who are in charge of cleaning. They are aware of the material being cleaned and carefully examine each item BEFORE cleaning, looking for secure placement of the gemstones. Also, it is prudent NOT to use this machine for diamonds and gemstones which are highly included with flaws, especially flaws which break the surface of the stone. Fractures and cleavages can be extended in the stone which can seriously undermine the durability.
I always point out the BEFORE appearance of the item to be cleaned. And, when the item has been cleaned it is once again what I like to call "showcase clean." One of the most rewarding aspects of this task for me is when I get a smile and a THANK YOU SO VERY MUCH from a client. I have had the good fortune of NEVER DAMAGING a diamond or gemstone using this method. Of course, I use my knowledge and careful technique in caring for the jewelry.

Polishing Machine

This is an industrial quality two-lap polishing machine. The laps are impregnated with what is known as "rouge." Different rouge is indicated for the type of metal being polished. The hoods over each wheel catch the minute metallic particles and filter them into a trap. Each accessible portion of the jewelry item is polished. The rouge acts as an abrasive medium which brings out the high metallic luster of precious metals. You can determine good craftmanship in a ring by looking at the INSIDE of the ring shank. The polish should be gleaming and mirror-like. There is NO EXCUSE for bad polish on any piece of jewelry that is manufactured. The jeweler stands in front of the machine and is in a position to fully grasp the item. Believe me, in this kind of work ONLY practice makes perfect!

Automatic Polishing Machine

This big red "box" is an automatic polishing machine. It employs the use of small stainless steel filings in a special solution in the bin on top. The filings are swirled around in the solution magnetically making contact with the jewelry item/s. The result is a fine matte polish on all surfaces. The model is made by the Romanoff Company of Amityville, New York. Note the MADE IN THE USA sticker on the upper left hand corner of the unit.

Vacuum Casting

There are two methods of casting precious metals. This machine uses the vacuum technique where the molten metal is literally "sucked" into the impression forming the item that is being made.
The other method uses a spring driven centrifuge which rotates at a high rate of speed. It is my opinion that the vacuum method is slightly superior in terms of better outcomes.