- Varieties of Chalcedony
- Formation & Sources of Chalcedony
- Chalcedony Jewelry
- Physical & Optical Properties of Chalcedony
- Test and Identification of Chalcedony
- Buying Tips for Chalcedony
Chalcedony is fashioned in a wide variety of shapes and forms, including beads, carved and engraved gems, pen stands, figurines, spheres, bowls and every variation of the cabochon cut. The larger piece, of agatized wood, agate and jasper are particularly popular for bookends, paper weights and similar objects. The majority of agates for commercial consumption are stained and cut at Idar-Oberstein, Germany. Large quantities of almost all chalcedony varieties are tumbled for use in earrings, dangle bracelets, pins and many other-jewelry articles.
Since chalcedony is one of the tougher gemstones, cutting does not present any of the usual problems tor the lapidary. Orientation is necessary only to obtain the desired pattern (scenes, flowers, trees, etc., in agate), or for color or fractures. It is not overly affected by heat, and only the usual care in dopping, grinding and sanding is necessary. Chalcedony is one of the easiest gemstones to fashion; hence, it is widely used in introducing the novice to the lapidary arts. It is usually polished on a felt lap, using tin oxide or cerium oxide as the polishing agent. A few of the jaspers that tend to undercut should be polished with Linde A or chromic oxide on a leather lap.
Because the Idar-Oberstein district is a world famous agate cutting center, a brief description of its activities and history is appropriate in this assignment. Idar and Oberstein, which are twin towns in the Idar Valley of the Nahe River in Germany's lower Saar Basin, have been noted for their lapidary craftsmen for almost two thousand years. One of the sights of Oberstein, which has a population of about 20,000, is an ancient church high up on a cliff above the river that is partly carved out of an old agate bearing lava flow. Idar, with about 12,000 inhabitants, forms that part of the twin town that lies in the steep-walled tributary of Idar Brook. The surrounding hills consist of old basaltic lava, in the steam cavities of which occur numerous concentrations of agate, crystalline quartz and calcite.
Legend and history have it that the industry had its inception in Roman times, when Caesar was pressing northward after his conquest of Gaul. It is said that in those days a troop of Roman soldiers crossed a mountain range and stumbled upon a small and unpretentious group of dwellings perched on precipitous walls of rock between which ran a rapidly flowing stream. The native presents and hunters all had collections of beautifully marked stones that they had broken from the rocks surroundings their village. Among these collections, the Romans, the Romans recognized the same materials from which the artisans and goldsmiths of the Imperial City cut and polished the precious stones that were so prevalently worn at that time. Thus began a period of lively activity in the little settlement, which was then known as Hidera. The water power of Idar Brook was harnessed and great grindstones were installed. By the year 31 A.D., Idar was an important gem-cutting center.
Although demand diminished with the fall of the Roman Empire, the
inhabitants never ceased their activity in the handicraft that had been
introduced to them. During the twelfth century, the Counts of Oberstein,
among other German lords who owned the lands and the quarries,
controlled the important business of supplying gems to adorn the armor
and swords of the knights and the attire of the castle maidens. The
fifteenth century saw a well-established lapidary industry that was
devoted entirely to cutting the material mined from local deposits. A
cutters guild was organized in 1609 that included three specific working
groups; the stone pickers, the grinders and the drillers. Soon the fame
of Idar-Oberstein and its superior craftsmen began to spread, and many
foreign buyers came
to the Idar Valley. In the early nineteenth century, when the supply of
rough material became almost nonexistent, the industry managed to
continue on a reduced scale by using Swiss rock crystal and smoky
quartz, Saxon and Bohemian amethyst, and Indian carnelian, moss agate
and jasper. In 1827 the Uruguay-Brazil agate fields were discovered by
emigrants from the Idar district, and the importation of this material
revived the languishing industry.
Today, the cutting works are located not only in the twin towns but in the surrounding villages and farms as well. The cutting of agate offers a supplementary source of income to farmers, woodcutters, and others during winter months and other periods of slack time. In past years, the numerous mountain streams furnished waterpower for the small mills along their banks. Electrically driven machinery has replaced the more picturesque waterwheels. The old fashioned manner of agate cutting so frequently illustrated in descriptions of Idar-Oberstein, which required that the cutter lie prone before a large sands tone-wheel, is now obsolete. Although Idar was fortunate in being saved from destruction during World War II, the industry suffered greatly as a result of lack of material and import and export difficulties. Since that time (however, the two towns, recognizing the historic interest of the industry and their commercial dependence on it, have taken steps to foster it. Schools to teach gemology and the lapidary arts. have been established to train new workers. Many craftsmen, as a means of bolstering the economic structured of the community, are now applying their talents to diamond cutting and the shaping of agate and synthetics into balance stones, mortars and pestles, bearings and many other kinds of scientific and technical apparatus. As a result of these and other constructive efforts , Idar-Oberstein is now more prosperous than ever before.
- Varieties of Chalcedony
- Formation & Sources of Chalcedony
- Chalcedony Jewelry
- Physical & Optical Properties of Chalcedony
- Test and Identification of Chalcedony
- Buying Tips for Chalcedony