Batu mulia dibagi menurut tingkat kekerasannya karena setiap batu mulia mempunyai tingkat kekerasan yang berbeda-beda. Semakin keras sebuah batu mulia, maka akan semakin tinggi tingkatan dan mahal harganya.
Diamond
Menurut Mohs, tingkat kekerasan dikategorikan dalam 10 mineral. Metode skala Mohs adalah kekerasan dalam hal tahan gores, yaitu membandingkan dengan cara melihat mineral mana yang dapat menggores mineral lainnya. Sebagai contoh, Corundum dua kali lebih keras dibanding Topaz, Diamond atau Berlian empat kali lebih keras dibanding Corundum.
Berikut ini daftar tingkat kekerasan untuk 149 batu alam menurut skala Mohs:
Diamond atau Berlian 10
Star Ruby 9
Ruby 9
Sapphire/Safir 9
Star Sapphire 9
Color-Change Sapphire 9
Chrysoberyl Cat’s Eye 8.5
Alexandrite 8.5
Chrysoberyl 8.5
Spinel 8
Imperial Topaz 8
Topaz 8
Azotic Topaz 8
Mystic Topaz 8
Rutile Topaz 8
Emerald/Zamrud 7.5 – 8
Aquamarine 7.5 – 8
Goshenite 7.5 – 8
Beryl 7.5 – 8
Morganite 7.5 – 8
Cat’s Eye Aquamarine 7.5 – 8
Andalusite 7.5
Hambergite 7.5
Ametrine 7
Iolite 7 – 7.5
Demantoid Garnet 7 – 7.5
Tourmaline 7 – 7.5
Rose Quartz 7
Kunzite 7
Chrome Tourmaline 7 – 7.5
Dumortierite Quartz 7 – 8.5
Rubellite Tourmaline 7 – 7.5
Quartz / Kuarsa 7
Cat’s Eye Tourmaline 7 – 7.5
Star Lemon Quartz 7
Mystic Quartz 7
Paraiba Tourmaline 7 – 7.5
Danburite 7 – 7.5
Rutile Quartz / Kecubung Rambut 7
Aventurine 7
Smoky Quartz 7
Amethyst/Kecubung 7
Citrine 7
Strawberry Quartz 7
Quartz Cat’s Eye 7
Star Rose Quartz 6.5 – 7
Color-Change Diaspore 6.5 – 7
Tiger’s Eye 6.5 – 7
Agate Geode 6.5 – 7
Hiddenite 6.5 – 7
Almandine Garnet 6.5 – 7.5
Cat’s Eye Diaspore 6.5 – 7
Pyrope Garnet 6.5 – 7.5
Mali Garnet 6.5 – 7.5
Tiger’s Eye Matrix 6.5 – 7
Sillimanite Cat’s Eye 6.5 – 7.5
Jasper 6.5 – 7
Grossularite Garnet 6.5 – 7.5
Fire Agate 6.5 – 7
Agate / Akik 6.5 – 7
Color-Change Garnet 6.5 – 7.5
Tsavorite Garnet 6.5 – 7.5
Hessonite Garnet 6.5 – 7.5
Bloodstone 6.5 – 7
Carnelian 6.5 – 7
Idocrase 6.5
Rhodolite Garnet 6.5 – 7.5
Peanut Wood 6.5 – 7
Peridot 6.5 – 7
Dendritic Agate 6.5 – 7
Onyx 6.5 – 7
Fossil Coral 6.5 – 7
Ruby-Zoisite 6.5 – 7
Star Garnet 6.5 – 7.5
Zircon 6.5 – 7.5
Axinite 6.5 – 7
Melanite 6.5 – 7
Spodumene 6.5 – 7
Chalcedony 6.5 – 7
Tanzanite 6.5 – 7
Chrysoprase 6.5 – 7
Rainbow Pyrite 6 – 6.5
Maw-Sit-Sit 6 – 7
Jadeite / Giok 6 – 6.5
Star Moonstone 6 – 6.5
Clinohumite 6
Amazonite 6 – 6.5
Cassiterite 6 – 7
Labradorite 6 – 6.5
Moonstone 6 – 6.5
Sugilite 6 – 6.5
Kyanite 6 – 7
Orthoclase 6 – 6.5
Nephrite Jade 6 – 6.5
Prehnite 6 – 6.5
Sunstone 6 – 6.5
Andesine Labradorite 6 – 6.5
Rainbow Moonstone 6 – 6.5
Star Sunstone 6 – 6.5
Rhodonite 5.5 – 6.5
Boulder Opal 5.5 – 6.5
Hematite 5.5 – 6.5
Moss Opal 5.5 – 6.5
Fire Opal 5.5 – 6.5
Cat’s Eye Scapolite 5.5 – 6
Moldavite 5.5
Scapolite 5.5 – 6
Sodalite 5.5 – 6
Opal Doublet 5.5 – 6.5
Hackmanite 5.5 – 6
Nuumite 5.5 – 6
Opal / Kalimaya 5.5 – 6.5
Tashmarine Diopside 5 – 6
Tremolite-Hexagonite 5 – 6
Smithsonite 5
Obsidian 5 – 5.5
Lapis Lazuli 5 – 6
Hemimorphite 5
Turquoise/Pirus 5 – 6
Chrome Diopside 5 – 6
Sphene 5 – 5.5
Star Diopside 5 – 6
Cat’s Eye Apatite 5
Snowflake Obsidian 5 – 5.5
Apatite 5
Larimar 4.5 – 5
Gaspeite 4.5 – 5
Charoite 4.5 – 5
Fluorite 4
Ammolite 4
Rhodochrosite 4
Variscite 4 – 5
Malachite 3.5 – 4
Sphalerite 3.5 – 4
Azurite 3.5 – 4
Verdite 3
Calcite 3
Coral 3 – 4
Pearl / Mutiara 2.5 – 4.5
Lepidolite 2.5 – 3
Chrysocolla 2 – 4
Seraphinite 2 – 4
Amber 2 – 2.5