Gem
A gem ( Latin gemma : bud, gemstone) is a cut gemstone or gemstone. The technical term for gemology and the name of the stone cutter ( Gemmarius ) are derived from this.
Today, a gem is usually understood to be a deeply cut gemstone: The picture motif is cut into the stone; these gemstones are also known as intaglio . In contrast, with a cameo or a cameo, the background of the motif is cut away, so the motif protrudes from the rest of the stone like a relief . In a broader sense, the gem can also be used as a generic term for intaglio and cameo to denote all cut gemstones and gemstones.
The preferred stone material is the quartz group (e.g. chalcedony ) in the form of layer stones . The oldest stone carvings were made in the 5th to 3rd millennium BC. The stone carving art of the Egyptians , Persians , Assyrians and Greeks was particularly high quality .
Gems were often used as seal stones (especially in the signet ring). The Alsengemmen are a special form of these gemstones .
Use of antique gems
The custom of closing something with a seal goes back a long way to prehistory in certain cultures. Babylonian cylinder seals already give evidence of this, and even today contracts and other important letters are still imprinted. The principle of imprints is to indicate the owner through the uniqueness of the seal, who guarantees the content. To make such impressions, as early as the beginning of the 4th millennium BC. Cylinder engraved in Mesopotamia . These cylinders and the first gemstones were initially provided with relatively simple symbols and images. With the advancement of the cutting technique, more and more complicated images were engraved on ever harder stones, but this was irrelevant for the actual purpose as a seal. The mass into which the engraved stones were imprinted varied - as is known from tradition and testimonies - beeswax and clay were particularly popular in ancient times, but lead was also used for this. Imprints of gemstones have also been preserved on vessels.
Cut stones could also be mounted on a finger ring and thus used both for carrying and showing and as a seal. A number of gems were also set differently and served as jewelry for a brooch or earrings . There are also numerous gems that were never set because they do not show any remains of glue or traces of ring settings. These stones may have been kept as collectibles because of their beauty and value. Sometimes they were valuable for the owner from a "magical" point of view as bringing luck or preventing damage.
Technique of gem cutting
The engraving of signs and images in smaller stones was already known in prehistoric times. Early engravings were all etched into soft stones with a graver. The forerunners of the first gems were created in the advanced cultures of the Near East and date from the 3rd millennium BC. These were gemstones that were used as roller or stamp seals , with the engraved characters already being made with drills or wheels.
The first gems in the early Greek world date from the 8th century BC. Chr .; they are provided with representations that belong to the geometric style . Back then, however, the technique of engraving with a rotating cutting tool had been forgotten. Therefore, soft stones such as serpentine , steatite and the like were used for the seals . a. used, which could be processed very easily with a hand-held graver. It was only through the Phoenicians that the highly developed stone-cutting technique was spread in the Mediterranean world and reached in the 5th and 4th centuries BC. A climax. Famous gem cutters from the Hellenistic era, the end of the Roman Republic and the beginning of the imperial era are also known by name (e.g. Phrygillos , Sosias etc.)
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At the time of the Roman Empire, from the 1st century BC. Until the 5th century AD, workshops for the production of gems were widespread and several gem artists were even on the move throughout the empire.
Apart from a few innovations relating to the type of drive, nothing has actually changed in the technology of engraving. The engraver attached the preformed gemstone to a base and moved the stone on the rotating pointer as he needed it for his cuts and indentations. The hands themselves were made of relatively soft metal and were made in different sizes, shapes and thicknesses. Their cutting marks are sometimes still clearly visible on gems. For some pieces you can still clearly see the use of different wheels and types of drills. However, many gems seem to have been made with simple tools, as their simple and rough design shows. The choice of the pointer shapes used was made by the gem cutter according to requirements, this was also determined by time and fashion.
The spherical, conical or wheel-shaped pointer made of soft iron was dipped in oil and diamond dust, which were used as cutting and grinding tools. By turning and turning the stone on the rotating pointer, engraving was then carried out. In this process, the stone was moved and not the pointer. The image had previously been scratched into outlines on the stone in order to make the cuts easier. As a control, intermediate impressions were taken and details were worked out with finer tools. Finally, the picture and the rest of the stone surface were polished to a glossy finish.
Stone types
The technique of gem cutting was already mature enough by the Roman Empire that all known jewelry and precious stones could be processed. For the selection of the gemstones, it was crucial that certain types of stone were always in fashion, whereby price criteria or delivery options also played a major role. Belief in the magical powers of stones also played no small role. Certain types of stone were usually preferred for certain groups of pictures: for magical or gnostic pieces, speckled multicolored stones such as hematite and chrysoprase were preferred , but bone is also an option . The manufacture and quality of the stones were also of crucial importance. Most of the stones were probably imported from the Near East and especially from the Far East, as Pliny describes in his naturalis historia for several types: emerald (XXXVII, 65), jasper (XXXVII, 115 ff.), Amethyst (XXXVII, 40 ) and sardonyx (XXXVII, 23).
The fashion trends of that time refer not only to the types of stone, but also to the colors of the gemstones. For example, in the early Roman Empire, darker gemstones were more in demand (e.g. carnelian , jasper ). The paler colors were again preferred by the end of the 2nd century AD.
gem by Lorenz Natter around 1740
Of the different types of stone, particularly between the 1st century BC In the 2nd and 3rd centuries AD the carnelian and jasper were popular in the 2nd and 3rd centuries AD. The onyx was especially popular in the 1st and 2nd centuries AD.
Glass pastes
Imitations of gems and cameos cast from glass, which also almost always imitate the colors and shapes of precious and semi-precious stones, are now called glass pastes. This is a name that is derived from "paste", the neo-Latin and Italian name for glass masses for the manufacture of precious stones. Glass pastes not only have common gemstone types, such as two-layer onyx, carnelian, chrysoprase and the like. a. imitated, but also offered their own color variation and fantasy areas that cannot be achieved by stones. Thus, the products were not only cheaper mass-produced goods, but they opened up gaps in the market that the stone glyptic could not cover. From a technical point of view, through careful observation, two basic types can be distinguished, which also require two different manufacturing methods.
- There are pastes with a rather rough surface. Almost all of them show traces of an impression on the back, which comes from an object with which the mass was probably pressed into a form. The paste had the motif in the mold. The molten glass was dripped into this shape, adapted with the edges, and pressed down with a rod inserted on the back.
- These are pastes with a very smooth image layer, the back of which is rough and pressed so tightly that pressure must have been exerted on the image layer. Here, too, presumably a mold with prepared edges was used, into which glass mass was dripped and pressed with a stamp, on the printed side of which the image motif was embedded.
The imitations are sometimes of such high quality that it is still difficult to identify them as glass and not as stone. The use of glass pastes is in no way different from stone clamps. They are also set in rings of any kind of metal. Gold rings in particular are particularly common. They also seem to have been used to seal soft material, as some pastes have a particularly stressed surface.
Image inventory
For centuries, the choice of motifs on the gemstones was dependent on changing trends in religious matters and developments in business and everyday life. Thus, the representations were influenced by faith and superstition, the hope of happiness, success, victory and fear of misfortune, misery and death. A large area includes topics dealing with the world of gods and patron saints. Another part of the image content on gems and cameos has also dealt intensively with Greek and Roman legends.
“Sacred” themes in particular had a dominant position in the presentations. Round sculptures and reliefs from cult sites or coins served as templates for these pictorial themes. The image content was mostly adapted to the time or the taste of the customer.
Presumably there was a kind of sample book for the gem cut, in which the most popular motifs were recorded in order to make it easier for the customer and also for the gem cutter to choose the motif.
At the end of the 2nd century after the birth of Christ, the influence of oriental religions and cults became particularly noticeable in the western world, which also had an effect on the contents of the pictures on gems. Representations of Egyptian deities, such as B .: Anubis and Isis , were also very popular.
See also
- Daktyliothek (gem collection)
literature
- Erika Zwierlein-Diehl : Antique gems and their afterlife. de Gruyter, Berlin a. a. 2007, ISBN 978-3-11-019450-0 .
- Günther Dembski: The ancient gems and cameos from Carnuntum . Phoibos Verlag, Vienna 2005, ISBN 3-901232-53-2 , ( Carnuntum Archaeological Park Neue Forschungen 1).
- Günther Dembski : Roman period gems and cameos from Carnuntum . Vienna 1969, (Vienna, Univ., Phil. Diss.).
- Regine Fellmann Brogli: Gems and cameos with rural cult scenes. Studies on the glyptics of the late Roman Republic and the Imperial Era . Lang, Frankfurt am Main a. a. 1996, ISBN 3-906751-70-8 , ( European university publications series 38: Archeology 59), (also: Basel, Univ., Diss., 1993).
- C. Pliny Secundus : Natural history . Volume 37: Stones. Gemstones, gems, amber . Artemis & Winkler, Munich a. a. 1994, ISBN 3-7608-1617-7 .
- Workshop report 20 of the artist service: Martin Seitz -Steinschnitte . Berlin 1942.
- Friend's edition to Martin Seitz : For his 75th birthday . Passau 1970.
- Peter Zazoff : The ancient gems. Beck, Munich 1983, ISBN 3-406-08896-1 , ( Handbook of Archeology ).
- Adolf Furtwängler : The ancient gems. History of stone cutting art in classical antiquity. 3 volumes (Volume 1: panels. Volume 2: Description and explanation of the panels. Volume 3: History of the stone-cutting art in the classical age. ). Giesecke & Devrient, Leipzig a. a. 1900 ( digitized version ).
