Gemstones are always minerals and have a high light refraction, warm colors, a Mohs hardness level of 8 or higher and a rare occurrence. The price of a gemstone is therefore much higher than that of a decorative stone and is calculated in detail according to rarity, weight, cut and purity. Internal and external features are also characteristic of gemstones: inclusions of liquids or gas bubbles, which are not seen as defects but as the stone's "fingerprint".
gemstone topaz
Mineral class : Topaz belongs to the class of silicates. The gemstone has a Mohs hardness of 8, making it one of the hard minerals and serves as a reference on the Friedrich Mohs scale.
Color : Topaz is available in many colors - from colorless to yellow, red, violet, blue, green and brown. Naturally colored blue topazes are relatively rare. The stone is often irradiated to achieve the blue color.
Distribution : The largest deposits are in Brazil, Russia, Pakistan, Sri Lanka and the USA.
ruby
Mineral class : Like sapphire, ruby belongs to the corundum gemstone group. After diamond, it is the second hardest mineral, according to Mohs, with a hardness level of 9.
Color : various shades of red.
Distribution : Myanmar, Sri Lanka, Thailand, Madagascar, Tanzania, Kenya, India, Cambodia, Russia, China, Vietnam
Special feature : with rubies, apart from the heating process that has been common practice for centuries (which does not need to be mentioned separately), there are many subsequent processing and refinement options.
sapphire
Mineral class : Sapphire, like ruby, belongs to the corundum group. After diamond, it is the second hardest mineral, according to Mohs, with a hardness level of 9.
Colour : Various shades of blue. There are also corundums of other colours – i.e. not blue – but they are still called sapphires! These then have corresponding names: colourless sapphires (also "white" or leucosapphire), yellow, green, violet, pink, orange sapphire, black sapphire (trade name "Black Star") and many more...!
Occurrences of these gemstones : Thailand, Myanmar, Sri Lanka, Australia, USA, Kashmir (depleted), China, Russia, Tanzania
