Gems Notes and Extracts Augusto Castellani, Mrs. John Brogden 1871

150 GEMS.The most ancient works in mosaic are found amongstthe Egyptian jewels. They consist of pieces of glassvariously painted, and in enchased gold setting.Many pavements of the Greco-Romano period weregreat mosaics of -square marble of every colour. Thiswork was called opus musivum.After the fifth century, mosaic was used in the wallsand ceilings of churches, no longer in heavy marble,but in bright square enamels, united and supported bya stucco,over a great surface, with the utmost exactness,of which we have a splendid example in theBasilica Constantiniana of St. Sophia, and St. Mark's atVenice.In jewels of the period of Charlemagne, carnelian,plasma, and other agates have been found, set in gold,like the enamel of Egyptian work.In the seventeenth century, at Florence, and soonafter at Dresden, they made mosaics of pietra dura,that is, of agate, jasper, and other gems, worked separatelyfirst into the desired form on the wheel, andthen fixed with cement into gold, bronze, or marble, toform elegant tables, beautiful ornaments, or prettyfeminine adornments.The mosaic workers of the Vatican, in the eighteenthcentury, began to make mosaics of glass, in very smallproportions, and thus originated the so-called Eomanmosaics, which were and are still executed by artistsof no little cleverness, who adapt this kind of workto every kind of ornament.