It’s the largest cut topaz that has ever been displayed, measuring in at 15 centimetres long and 10.5 centimetres in width and weighing an impressive 9,381 carats. One of the displays includes the Ostro Stone, which is a flawless blue topaz discovered by a British explorer in Brazil several decades ago. London is also home to the United Kingdom’s Natural History Museum, which houses a famous gallery of minerals. London Blue topaz refers to the darkest, richest colour of topaz available on the market.

One of the most popular theories for this stone being called London Blue topaz is because London has a bit of topaz prestige tied to it. However, there are conflicting reports on whether or not the geographical locations tied to the stones have anything to do with their origins. There’s a bit of a debate surrounding where London Blue topaz got its name, particularly because its lighter counterpart is referred to as Swiss Blue topaz. The latter three are classified as gemstones, while topaz is classified as a mineral. While harder than quartz, London Blue topaz is not as hard as sapphires, rubies or diamonds. It measures in with a hardness of eight on the Mohs scale, which means that it is harder than quartz although it often grows alongside it. The topaz stone is composed of fluorinated aluminium silicate. In fact, the colour is best described as a halfway point between the two. It’s darker than regular topaz but lighter than a sapphire. What Is London Blue Topaz?īy definition, London Blue topaz is a topaz stone that has a very specific, inky shade of blue. Let’s take a closer look at this gorgeous blue stone and learn a little bit more about it. It’s often confused with blue sapphires, but the two are actually quite different. The stone has a specific hue of blue that makes it look almost inky and sets it apart from regular blue topaz, which is also known as Swiss Blue topaz.

London Blue topaz has a fair bit of mystery and intrigue surrounding it.

Dark sapphire stone