ROUGH GEMSTONE PRICES
Rough gemstones, including certain organic materials, but not pearls, are listed alphabetically with cross references for varieties. Each entry is preceded by appropriate statements of characteristics, sizes, qualities, sources, etc. Not all varieties are included because so many of them, espe¬cially among the numerous members of the quartz family, are no more than […]

SELECTION OF CARVING ROUGH
While it may seem that more latitude can be taken in respect to internal defects when choosing large rough for carvings, this is really not the case. As a matter of fact, it is far more difficult for the carver to obtain satisfactory rough than the cutter of gems. Because some types […]

IMPREGNATION OF ROUGH TO DISGUISE DEFECTS
Knowing that cracks detract from the value of rough, some overseas dealers in large parcels of rough, notably Brazilian and Indian dealers, sometimes practice a deception which the buyer should guard against.

QUARRIED MATERIAL
Much cabochon rough is extracted from its host rock by the use of considerable physical force, perhaps even explosives. Sometimes the quarried blocks are so large that they cannot be easily transported and must be further broken down into manageable pieces by means of sledge hammers. If the material is valuable throughout, it may […]

MOONSTONES
The finest moonstones are feldspar gemstones occurring in Burma and Ceylon. Both countries provide rough remarkable for its high degree of translucency, almost water-clear in some specimens, and the presence of minute inclusions which give rise to a beautiful silvery or blue sheen. Any rough requires careful inspection before purchase because of the tendency of […]

SELECTION OF CHATOYANT ROUGH
The term chatoyant is used to designate the silky sheen caused by very small reflecting inclusions of a fibrous nature which lie in parallel posi¬tion in certain gemstones. Strictly speaking, all star gems are chatoyant, but the chatoyancy occurs in several directions at once while in ordinary chatoyant gems, such as catseye […]

CABOCHON MATERIAL
Flawlessness in cabochon material is not as crucial as it is in facet material; however, large flaws or surface cracks which tend to trap polishing powder, pores, soft inclusions which may pit during polishing, and other gross defects can result in unsightly gems. In very valuable materials such as star ruby and corundum, which […]

ORIENTING SYNTHETIC RUTILE
In view of the troubles many cutters have had with the highly double-refractive synthetic rutile, a few words on how to locate the direction along which the least blurring will occur in finished gems are considered worthwhile. This direction coincides with the optic axis. Synthetic rutile is usually sold in boules or cylindrical […]

COLOR AND COLOR DISTRIBUTION
In many gemstones, color tends to be uniformly distributed in the rough, and the lapidary’s only concern is that of cutting the largest gem consistent with the shape of the rough. In other gemstones, however, the color may be unevenly distributed or even changeable in character from place to place as shown […]

EFFECTS OF FLAWS AND INCLUSIONS
Ordinary cracks and fissures are abundant in many gemstones but may also arise during trimming of the rough by miners and dealers. When¬ever possible, cracked rough should be avoided for the reasons explained below. If the edge of a crack intrudes into a clean area, one may be sure :hat the […]