Gemmology On A Shoestring

2007: B W Anderson is one of the god fathers of gemology. His inspiring note (s) on how to identify stones with simple instruments + warning the gemologist (s) against an over dependence upon instruments + the need to use the power of observation (s) to the full + interpret what is seen in simple terms, is a friendly reminder to any enterprising gem dealer/jeweler.

Today we have new diamond simulants like synthetic cubic zirconia, synthetic moissanite and others + new synthetic corundums + new synthetic diamonds + new synthetic beryls + new, modified colored stone treatments to keep gem dealers/jewelers/gemologists/ lab gemologists busy/awake for the rest of their lives.

(via The Journal of Gemmology, Vol.10, No.3, July 1966) B W Anderson writes:

On several occasions I have given talks to post-diploma students under the title ‘Gem testing without instruments’, which I believe have been helpful in warning the student, fresh from his examinations, against an over-dependence upon instruments in his endeavors to identify gemstones. ‘Gemmology on a Shoestring’ is intended to follow much the same theme, but the title purposely suggests a little latitude in allowing for the use of quite simple pieces of apparatus, liquids, and so on, which can aid considerably in making firm decisions instead of merely forming opinions in certain cases.

First I must make it quite clear that to solve many of the problems that confront the gemologist in these days every available instrument may be valuable and necessary if a correct answer is to be ensured. My present intention is not so much to provide easy recipes for individual cases of identification as to persuade those who have gemological training to use their powers of observation to the full and interpret what is seen in the light of their special knowledge. It has often been said that the limited amount of scientific knowledge absorbed in the two year course can actually be a handicap to a young jeweler: into every yellow zircon he dreams a sphene, and in viewing a parcel of tourmalines his mind is cluttered with thoughts of kornerupine. There is enough truth in this to sting a little; but I strongly maintain that in a ‘lens only’ identification test on mixed series of gemstones, the man with a gemological training should be far more sure of his ground than a colleague of otherwise equal ability and experience. As any good artist knows, it is a fallacy to think that any two people of normal eyesight gazing at a given object are necessarily seeing the same thing. It is the interpretation of the image falling on the retina that may enable the artist to see a significant and exciting pattern of shapes, shadows and colors, where his friend may see nothing of any interest whatsoever. In like manner a jeweler who is not a gemologist, when confronted by a mounted and well-cut white zircon, may well feel that it ‘doesn’t look quite right’ for a diamond, but his gemologist friend, noting the strong double refraction in the stone, will be able to make a quite positive identification.

Sheer economic necessity may deprive the average young gemologist of the three really essential instruments for gem identification—the microscope, refractometer, and spectroscope. Ten years or so ago less than fifty pounds would have been required to but the lot: today one may have to pay at least twice as much as this. Indeed the simple liquids which will be recommended in this talk are now so costly that one must ruefully admit that even ‘shoestrings’ have become expensive. Against this one must realize that in the precious stone trade a mistake mean a loss of hundred of pounds or a damaged reputation, and the cost of any instrument which can save such mistakes, or a fee for a laboratory test, is money wisely spent.

To start with, I shall assume that the jeweler has only one ‘instrument’—a pocket lens, and proceed to consider what he can learn about gems with this as his only aid. A good lens is so vitally important that I do insist—make it a good one, magnifying eight or ten diameters. Lower powers are of comparatively little use, however suitable for the scrutiny of watches or hallmarks—while higher powers are difficult to handle and not nearly so flexible in their application.

In our first assessment of any gemstone we are all inevitably influenced in our thinking by its general appearance, which, when analyzed, depends chiefly upon its color, luster, degree of transparency, and ‘fire’. If the stone is unmounted, we may notice from our first ‘feel’ of it is cold or relatively warm to the touch, that it gives a slippery or harsh impression when handled, or that it strikes one as ‘heavy’ or ‘light’ in the hand. Then may follow close examination with a lens. The back facet edges may appear doubled, there may be characteristic inclusion, cleavage chips may appear on the girdle, and so on. All these phenomena may either be accurately measurable or more closely investigated with instruments: our task is to learn all that we can without them—even if later some form of instrument may have to be used as a final court of appeal.

Gemmology On A Shoestring (continued)