A home Gemology Laboratory: Recommended Gemology Tools and Instruments

Gemology involves studying the optical and physical properties that make gems such unique little treasures. Gem identification involves analyzing these properties to differentiate one species from another. There are a number of gemology tools used to distinguish or measure these properties.

Tool	Vendors	Estimated Price
Microscope	GEMORO® Elite 1030 Microscope	€430.00
Loupe	10X Gesswein® 20.5mm Hex Triplet Loupes - Black	€21.95
Tweezers	D-Master Soft Tip Tweezers	€29.95
Scale	GEMORO® Platinum XP500 Scale (Capacity: 500g)	€29.95
Spectroscope	Handheld Durable Small Diffraction Spectroscope 55mm	€26.90
Refractometer	Ade Advanced Optics GL500 Gem Refractometer	€99.99
Calipers	4" Electronic Digital Pocket Caliper	€36.05
Diamond tester	Diamond Tech Pro Diamond Tester	€105.95

Getting Started: Gemology Reference Materials

Gemology Tools: The Essentials

• Loupe : You'll need magnification. Start with a good quality 10x (ten power) loupe. Some economy loupes on the market range from mediocre to very good quality.
  The best you can get, and the standard for diamond grading, is a color corrected triplet loupe. Triplet means it has three lenses, so there's no distortion near the edges. Color corrected refers to a coating on the lenses, so the color you see is accurate.

• Microscope : You'll also need a microscope for studying inclusions. This is often the only way to separate natural gems from their synthetic counterparts. While the loupe is more portable, the microscope is easier on the eyes and offers higher magnification. A gem microscope has special features that aren't available on most microscopes, so be sure the microscopes you're considering are appropriate for studying gemstones. A minimum 40x stereo microscope is needed for gemstone identification, but, of course, more power is helpful. You'll be able to see more inclusions and greater detail under higher magnification. Higher power will sometimes mean the difference between making an identification or not.
  As a general rule, purchase the highest quality instruments you can afford. With microscopes, however, you can make a compromise for your budget's sake without a significant sacrifice in quality. The bottom line is that the information gathered from a microscope has more to do with the skill of the operator than the quality of the optics.

• Refractometer : Measuring the refractive index (RI) of your gems will be a high priority. You can do this with a microscope, but a refractometer is the best tool. Besides measuring the RI, a refractometer will give you the birefringence and optic sign of a gemstone.

• Balance Beam Scale and Heavy Liquids : Another gem lab necessity is a means to measure specific gravity (SG). There are two methods for doing this. A balance beam scale can be used, provided one pan can be submerged in water. (That's usually easy to arrange). The other method is to use a set of "heavy liquids." This is a collection of liquids with predetermined SGs. You determine the specific gravity of a gem by submersing it in the liquids and observing whether it floats or sinks.
  Heavy liquids have some disadvantages. They are toxic and flammable, so you must exercise care when using and storing them.  Sometimes it's difficult to wash off the gem. Furthermore, your readings will always be estimates with heavy liquids. If you have an accurate scale, you can get a much more precise reading. There will be occasions when this is important, as a small fraction can sometimes confirm or eliminate a possible identification.

• Dichroscope : Next on the list is one of the most inexpensive gemology tools. The dichroscope is a small, hand-held instrument that separates the colors in dichroic materials. Its essential elements are two small pieces of polarizing material, oriented at 90º to each other, plus magnification.

• Polariscope : Equally important (and just a little more expensive) is a polariscope. It's used in conjunction with a loupe or a strainless (not stainless) sphere, which is a glass sphere with no strain lines in it. These are used to determine if a material is singly or doubly refractive and to ascertain its optic sign. The polariscope will also show strain and twinning, which will occasionally help to distinguish between natural and synthetic materials. (If you can't ascertain the optic sign with a polariscope, use a refractometer).

• Spectroscope : If you're serious about gemology and gem identification, you'll need a spectroscope to study a gem's absorption spectrum.
  There are essentially two different kinds of instruments, diffraction grating and prism. They both do equally well, but the scale is more elongated in the prism style.
  If you're relying on images in a reference book to help you determine what you're seeing, make sure they show views from your kind of spectroscope. Otherwise, the comparisons get very confusing.

• Calibrated Scale : Another important feature is a calibrated scale. Many people learn to use a spectroscope without a scale and make their determinations strictly by the colors. This ability depends on your eyesight and experience. 
  Until you've looked at enough gems, making an accurate assessment in this manner will be difficult. Thus, a spectroscope with a calibrated scale is preferable for beginners. However, a calibrated scale increases the price tremendously, so you'll need to consider this when budgeting for equipment.

• Lighting and Stands : Other factors that add to the price of a spectroscope include lighting and a stand. You need both a bright light source and a means to hold the gem, the spectroscope itself, and the light source steady while you're taking your readings. If these are all built-in, the spectroscope will be easier to use but also more expensive. If you're handy with DIY, you can create these elements and save some money. 
  There are inexpensive diffraction grating spectroscopes on the market. However, these are the most difficult to use. You must find a way to hold them very still in relationship to the gem and the light. To further complicate this, you focus a diffraction grating spectroscope by moving it closer and further from the gem. Since the display is much darker than a prism spectroscope, lighting is a particular consideration. 
  The spectroscope is one of the last gemology tools you'll need to add to your lab. If you have a tight budget, this instrument will take the most consideration. Prices can run up to a thousand dollars for top-of-the-line instruments with all the accessories. Get the best instrument you can afford, then make your compromises on the lighting and stand.

Miscellaneous Gemology Tools

The above instruments represent the major, "must-have"s of a gem lab. Of course, you'll also need a bunch of other odds and ends, such as:

• A gem cloth for cleaning your gems or some kind of strainer so they don''t go down the drain if you clean them in the sink
• Tweezers or a gem holder to hold your stones
• Small glass dishes for immersion studies
• A stone line to lay your stones side by side and upright for grading
• Calipers or a micrometer
• A scale to weigh your stones (no't a necessity for learning but a high priority for trade)
• Jewelers eye ; There's an instrument called a "jeweler's eye" or reflectometer that measures luster. It was designed for traveling professionals who need portable instruments, not beginners.

• Diamond tested ; If your work requires you to identify small stones in settings, a diamond tester is a necessity. Small, dirty, low-quality diamonds are impossible to distinguish with the naked eye.

• Hardness sets : Hardness sets or points, pencil-like things with ends made of varying materials, are a standard part of the mineralogist's toolkit. They're used to determine the hardness of a substance. These are also useful gemology tools if you're going to identify gemstone rough. However, never use these on finished gems. Hardness points will leave a permanent scratch and may cause a gem to break. If you're testing rough, make sure you test a small area that's separate from the cuttable portion, because stress on cleavage planes can cause the stone to split.

Lighting for Your Lab

Your lighting needs careful consideration. Standard lights will suit most of your needs, but you'll need something that is flexible and easily moved into useful positions. A flexible arm light, or even a good quality flashlight, will be very helpful. Some of your gemology tools and instruments will have built-in specialty lights. You may need to create or provide your own speciality lights for others.

Keep in mind that incandescent and fluorescent light will give you different colors in some gems. If at all possible, use incandescent or natural sunlight from a window as your primary light source. If your lab has fluorescent lighting already installed in the ceiling, you'll need to turn it off or shield it at times.

One of your most useful light sources is a window with indirect light, since filtered sunlight is the standard for color comparison. Also, don't make the mistake of thinking you can rely on daylight equivalent lights for color change comparisons. They work well in many cases but not well in others. More than one gemologist has been embarrassed by relying on artificial lights.