The process of initial gem identification, makes use of studying a stone's specific gravity, hardness, optical density and the presence of inclusions. Interpreting these observations in the context of gemology can help separate real gemstones from their fake counterparts.
1. Check your Gemstone's Heft by Bouncing it on Your Palm.
Using your open palm, bounce the stone around the center of your hand to get an idea of its heft. Every gemstone has a property called specific gravity that will determine how much it weighs at a certain volume or size. Even an average person can use an item's heft to rule out lighter imitations such as transparent gemstones made from plastic. The presence of mould lines or mould marks on facet surfaces can also help to give plastic or resin imitations away.
2. Search for Rounded or Curving Facet Junctions.
Look at the edges of your stone's individual facets. Some glass imitations will give you the impression of having rounded facet junctions, which would never be observable in a natural gemstone. This is because natural gemstones are mined from the earth and cut using hard abrasive materials. They therefore get very sharp facet edges in the process. Certain glass imitation gems are actually molded from molten silica material. An evidence of this would be that their edges are more curved than they ought to be.
3. Loupe Your Stone, Check for Any Inclusions at All.
Examine the interior of a stone with a 10x triplet loupe. A standard magnifying glass is not enough. Loupes are the minimum requirement for studying the inclusions within a gemstone. Certain inclusions can prove that a gem actually came from deep beneath the earth. Other inclusions, or a lack of them, can also sometimes indicate that a stone was synthesized in a laboratory. This may take practice and experience, but observation under magnification is one of the most reliable ways to identify gemstone species.
4. Consider the Design, Craftsmanship and Markings of its Setting.
Examine the metal setting of a gemstone if it is already mounted on a piece of jewelry. Sometimes the design can help give you clues about the stone itself. Large, brilliant stones with intense saturation should not be seen on metal mountings that are poorly constructed. Hallmark stamps can also be clues in your identification process. Silver settings are often stamped with a '925' mark, for 92.5% silver, the requirement for sterling silver. A five carat natural, untreated diamond for example, would be an unlikely sight on a silver banded ring. All these indications are not 100% however, only hints that can definitely help you make a smart estimate of your stone's nature.
5. Observe and Note Down the Hardness of Your Stone's Surface.
Check for any signs of wear-and-tear or scratches. Certain gemstones like diamond, are actually very hard. These stones would be less likely to display abrasions along facet junctions, or multitudes of scratches on the surface. Use reflected light to observe the texture of a stone's facets. Bumpy or "orange peel" texture is also an indication that the stone may be a moulded glass imitation.
6. Determine the Other Properties it Possesses as a Mineral.
If you possess a gemological setup, such as a desktop refractometer, polariscope and spectroscope, you can study a material's unique properties and use this information to deduce its identity. Although this sounds simple enough, it does require a considerable familiarity with the field of gemology. If you are uncomfortable taking or interpreting this information, or lack the necessary instrumentation, find a third-party laboratory to do it for you. Eliminate the guesswork with facts and science. Feel free to contact our laboratory gemologists for assistance on your stone.
Be very cautious about using handheld 'diamond testers', these make use of thermal conductivity (some use electric conductivity), and do possess a lot of limitations on their usage and precision. Thermal-based diamond testers, as well as many dual testers can misidentify moissanite as diamond. Neither instrument is also able to detect evidences of a stone being man-made, i.e. lab-grown diamond will fool them easily. Gain awareness above the marketing of these tools. They are useful in their own right, but not foolproof by any means. The misuse of tampered, outdated, or even standard testing instruments is especially rampant here in the Philippines today.
