1990s fancy yellow sapphire and diamond tank ring in 18kt yellow gold

1990s fancy yellow sapphire and diamond tank ring in 18kt yellow gold. Centrally set with a square step cut fancy yellow sapphire in a rubover setting, surrounded by round brilliant cut diamonds in grain settings, to a stylish three-dimensional cluster design featuring a chunky fan, polished gallery and broad integrated shoulders which curve to a solid shank. Hallmarked 18kt gold, Italian.