Gemology: S is for ...
Our 19th journey into the realm of gemology brings you the many gemstones beginning with S. Here we take a look at Saltwater Pearl , Sapphire, Sard, Sardonyx, Saussurite, Scapolite, Scheelite, Schorl, Selenite, Septarian, Seraphinite, Serpentine, Shell, Shell Pearl, Sillimanite, Sinhalite, Smithsonite, Smoky Quartz, Sodalite, South Sea Pearl, Spectrolite, Spessartine / Spessarite, Sphalerite, Sphene / Titanite, Spinel / Spinell, Spodumene, 'Star' Gemstones, Stichtite, Sugilite, Sunstone, and Swarovski.
Pearls are formed in molluscs that live in either freshwater (rivers) or saltwater (oceans and inlets). Saltwater pearls are from molluscs found in the sea.
Sapphire is the gemstone quality variant of the mineral corundum, occurring in many colours except red – red sapphires do exist, but they're called rubies! Sapphires are more widely known for being blue, so other colours have their name stated, i.e. green sapphire, pink sapphire, yellow sapphire etc.
Sapphires are very hard gemstones, second only to diamonds, and so are suited to a full range of jewellery uses. Sapphires can be translucent to opaque depending on the inclusions, with some sapphires displaying asterism (a star form within the gem, usually seen in opaque gems which are then polished en cabochon to enhance the feature), and pleochroism, the colour changing ability to appear one colour in natural light, and another colour in incandescent light, like Alexandrite.