1920's Portrait Colour Change Sapphire Intaglio Seal unisex They date from the 1970s

They date from the 1970s and are modelled in 9k gold throughout

Knoll and Pregizer were established in 1887 and quickly made a name for themselves making silver and paste jewellery

The stone is a gorgeous cushion shaped green spinel

Perfect size to weight ratio

1920's Portrait Colour Change Sapphire Intaglio Seal unisex They date from the 1970sDATE: Art Deco, c. 1920 A fantastic colour change sapphire (synthetic) seal, with a intaglio carving to the base. It's carved with a ladies portrait and the stone changes from a bluey purple to a turquoise green when moved from electric light to daylight. It remains in great condition and dates to the Art Deco period, circa 1920. Colour change gemstones possess the ability to appear as two completely different colours depending on the type of light