Swiss Blue Oval Blue Topaz from Africa

About Blue Topaz

Blue topaz ranges from a very pale, airy blue to stronger medium and deep blue. Trade names such as Sky Blue, Swiss Blue and London Blue describe shades rather than officially defined varieties. It is usually transparent, with a bright vitreous lustre and only weak pleochroism, meaning that its colour can vary slightly with viewing direction. Topaz is an aluminium fluorosilicate mineral, with a Mohs hardness of 8. This makes…