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A Hard Gem is Good to Find

The Mohs scale is the default hardness measure for gemstones. It runs from 10 as maximum hardness down to 1. It is somewhat arbitrary and not linear. The range from 9 to 10 is @ much greater than 8 to 9.

Harder minerals tend to be more durable and will not scratch easily. They endure well in jewelry.

Talc, with a Mohs hardness of 1, is the softest mineral and can be scratched with a fingernail.

Quartz is the most common gem mineral (Citrine and amethyst) and ranges at 7 and above.

Toughness - the ability of a gemstone to withstand pressure or impact. Minerals that crumble into small bits or to a powder are considered brittle.

Some minerals are tough because the manner in which the crystal structure has formed. Jadeite and nephrite are the toughest gems.

For gems that are brittle or easily broken, settings play an even more important role ... gem settings.

Gem Hardness Table

Diamond 10
Silicon carbide 9.25
Ruby & Sapphire 9
Chrysoberyl 8.5
Synthetic cubic zirconia 8.5
YAG 8.25
Spinel 8
Topaz 8
Taaffeite 8
Rhodizite 8
Beryl (emerald/aquamarine) 7.5-8
Zircon (high/medium) 7.5
Almandite garnet 7.5
Rhodolite garnet 7-7.5
Pyrope garnet 7-7.5
Spessartite garnet 7-7.5
Tourmaline 7-7.5
Andalusite 7-7.5
Iolite 7-7.5
Grossular garnet 7
Quartz & Synthetic 7
Danburite 7
Chalcedony 6.5-7
Peridot 6.5-7
Jadeite 6.5-7
Andradite garnet 6.5-7
Kornerupine 6.5
Zircon (low) 6.5
GGG 6.5
Spodumene 6-7
Sinhalite 6-7
Epidote 6-7
Zoisite (Tanzanite) 6-7
Orthoclase 6-6.5
Nephrite 6-6.5
Pyrite 6-6.5
Benitoite 6-6.5
Marcasite 6-6.5
Amblygonite 6
Labradorite 6
Hematite 5.5-6.5
Rhodonite 5.5-6.5
Brazilianite 5.5
Moldavite 5.5
Opal 5.5
Diopside 5-6
Glass 5-6
Strontium titanate 5-6
Lazulite 5-6
Lazurite (lapis lazuli) 5-6
Turquoise 5-6
Sodalite 5-6
Sphene 5-5.5
Obsidian 5-5.5
Bowenite (serpentine) 5-5.5
Apatite 5
Dioptase 5
Smithsonite 5
Synthetic turquoise 5
Apophyllite 4.5-5
Fluorite 4
Rhodochrosite 3.5-4.5
Malachite 3.5-4
Azurite 3.5-4
Coral 3.5-4
Conch pearl 3.5
Calcite 3
Black coral 3
Hemetine 2.5-6
Pearl 2.5-4.5
Jet 2.5-4
Serpentine 2-4
Amber 2-2.5
Copal 2
Alabaster 2
Steatite (soapstone) 1-2.5