Synthetic, imitation & enhanced gemstones
Synthetic gemstones: Synthetic gemstones are man-made. They are created by growing the crystals in laboratories that simulate the heat and pressure of volcanoes. But although the chemical structure is usually the same as the natural gemstones, the colour differs and instead of inclusions – those tiny crystals and cracks filled with liquid or gas that are the significant features of all natural gemstones – streams of little gas bubbles can be seen. Synthetic gemstones are used by the watch industry, in scientific instruments and in silver or costume jewellery collections.
Imitation gemstones: Imitation gems, made of glass, porcelain and artificial resins, have been made since the days of the ancient Egyptians. They are used in costume or fun jewellery but are also seen in some wonderful antique pieces that are highly prized by collectors.
Composite gemstones: Composite stones are created by placing as slice of the gemstone between glass, quartz or spinel. Most common are opal doublets and triplets and garnet topped doublets which Victorian goldsmiths frequently used as a substitute for emeralds.
Treated or enhanced gemstones: Treated or enhanced gemstones are those that have been heat and laser treated to enhance their colour, or to remove and fill cracks and inclusions. The stones should be described as ‘treated’ or ‘enhanced’. Most emeralds are oiled to enhance their colour but as the practice does not change the structure or colour of the stones, the jewellers do not generally describe them as such.