Stone Mania

In 1812 the Viennese mineralogist Friedrich Mohs introduced the term 'scratch hardness' which he defined as being the resistance of a mineral when scratched with a pointed tool.  To test the hardness of a mineral, he set up a comparison scale using ten minerals of differing hardness and the scale which is now known as 'Mohs scale of mineral hardness', is still widely used today.

The softest mineral on Mohs scale of mineral hardness is Talc which is graded 1, this can be scratched by Gypsum which is a 2 and Gypsum in turn can be scratched by Calcite which is 3.  Each mineral on Mohs scale of mineral hardness scratches the previous one which is less hard and in turn can be scratched by the one which follows which is harder.  Those which are the same hardness will also scratch each other.  Half grades are also used and all known minerals are allocated to Mohs scale.

Below are some of the gemstones featured in our collection and their hardness.

Chrysocolla 2 to 2.5.  Silver 2.5 to 3 hence another alloy needs to be added to it to increase its hardness.  Pearl (including Mother of Pearl) 2.5 to 4.5.  Serpentine 2.5 to 5.5.  Coral (we only use Sponge Coral and Fossilized Coral) 3 to 4.  Anhydrate (see Angelite ) 3.5.  Malachite, Azurite 3.5 to 4.  Rhodochrosite, Fluorite, Ammonite 4.  Kyanite 4 to 7.  Hemimorphite, glass 5.  Obsidian 5 to 5.5.  Lapis Lazuli, Turquoise, Charoite 5 to 6.  Moldavite, Enstatite (see Bronzite) 5.5.  Sodalite, Rhodonite, Opal, Hematite 5.5 to 6.  Zoisite (see Ruby Zoisite), Sugilite, the mineral Rutile (see Rutilated Quartz), Pyrite, Prehnite, Moonstone, Labradorite, Aventurine Feldspar (see Sunstone), Amazonite 6 to 6.5.  Epidote (see Unakite) 6 to 7.  Tigers Eye, Peridot, Jasper, Jadeite (see Canadian Jade and Nephrite Jade), Chrysoprase, Chalcedony, Agate, Zircon, Garnet 6.5 to 7.  Rose Quartz, Smoky Quartz, Quartz, Prasiolite (Green Quartz sometimes incorrectly referred to as Green Amethyst), Citrine, Aventurine, Amethyst 7.  Tourmaline, Iolite 7 to 7.5.  Dumortierite 7.5 to 8.5.  Emerald, Beryl, Aquamarine 7.5 to 8.  Topaz, Spinel 8. Sapphire, Ruby.