http://jewelryfindings.org Sat, 08 Dec 2007 03:20:26 +0000 http://backend.userland.com/rss092 en TUMBLE-POLISHED BAROQUES AND CABOCHONS Large quantities of irregularly-shaped gems, known as baroques or tumbled gems, are now prepared very cheaply by tumbling pieces of rough in barrels along with suitable abrasives and liquids, and later, with polishing agents. The process takes many days or even weeks, depending on the kind of ... http://jewelryfindings.org/?p=27 CHECKING POSITION OF OPTICAL EFFECTS To determine the strength, perfection,  and  position  of any  special optical effect, stand beneath a single pinpoint source of light, e.g., a single electric bulb (not a fluorescent light) or the sun. Diffuse light, such as that found out-of-doors on a cloudy day, results in broad, ... http://jewelryfindings.org/?p=25 ADDITIONAL NOTES ON STAR AND CATSEYE GEMS, MOONSTONES, ETC. As previously explained, star- and catseye-causing inclusions, and those responsible for moonstone, sunstone, and other sheen or color effects, occur in certain planes in the host crystal. It is up to the cutter to examine the rough to determine how he can ... http://jewelryfindings.org/?p=23 PROPORTIONS OF CABOCHONS The proportions of cabochon gems vary widely, some being quite thin in relation to their width, others being quite thick. Gemstones displaying star, catseye, and moonstone effects must be cut reasonably thick to "sharpen" the lines of light in the case of the first two and to induce ... http://jewelryfindings.org/?p=22 CABOCHON GEMS Because cabochons are entirely hand-shaped, the final curved surfaces depend for their geometrical perfection upon the skill of the lapidary. The ideal cabochon should be symmetrical in profile and outline, both of which can be easily determined by visual inspection. http://jewelryfindings.org/?p=20 SURFACE FINISHES Maximum brilliancy in any faceted gem is achieved only when the facets are cut as fiat as possible and polished to the highest degree of smoothness. The quality of surface finish is highly important in cabochon gems also, particularly in those displaying special optical effects such as star stones, ... http://jewelryfindings.org/?p=19 CULET FACET . There is no question that this facet destroys the ability of a small area near the tip to properly reflect light, yet, through long-standing tradition, this culet is still placed on brilliant cut gems. http://jewelryfindings.org/?p=18 NATURALS If one examines a parcel of round diamond brilliants, he is sure to see, sooner or later, a peculiarity which is confined only to the diamond. This is the existence of small flat spots along the girdle, called naturals, which glisten brightly in marked contrast to the dull surface of ... http://jewelryfindings.org/?p=16 THE GIRDLE AS AN INDICATOR OF QUALITY By examining the accuracy with which the facets of the crown meet the facets of the pavilion along the girdle, even the inexperienced person is able to judge the relative skill of the lapidary. It goes without saying that the skilled workman will pay ... http://jewelryfindings.org/?p=14 GIRDLES The thin band which separates the crown, or top of the gem, from the pavilion, or bottom, is know as the girdle. It may or may not be polished, or covered with very small facets. A girdle which is too thin is likely to chip when the jeweler sets it ... http://jewelryfindings.org/?p=12