Coral Marcasite & Silver Ring. Sterling Silver is Silver metal with Silver content of 925 parts in 1000. This ring is stamped 935, signifying an origin of either Germany or Austria in the Art Deco period  of between 1919 and 1939, approx. Completely handmade, with three terraces of gemstones, sixteen small red gemstone Corals in the outer ring, 12 cut and dully gleaming “marcasite” Pyrites in the inner ring, and a central fine red 5mm round Coral.
The Coral centre gemstone is bezel set; the smaller twenty-eight gemstones are all neatly bead-set and fixed in their scalloped outer bezels.
Note the six spaced little granules around the centre Coral bezel setting; a nice touch, unobtrusive yet stylish.

Marcasite and Pyrites are both iron sulphides and both over the ages have been used in small cuts to trick out artefacts and pieces of jewellery. Marcasite, however, is more brittle, unsuitable for jewellery. When the use of “marcasite” in jewellery became quite popular in Victorian times, the term marcasite applied to both the iron sulphides, and though it was only ever pyrites that was used, for its greater toughness and durability, the term marcasite stuck.
The origin of the Coral in the above ring is, of course, the Mediterranean, off the coast of Sicily, source of the Coral gemstone for Europe and its environs since antiquity.