🔷 Gems by Facetability

Gems grouped by brittleness/facetability

Excellent Facetability

Gem Hardness Mineral Group
Diamond 10 Carbon
Black Diamond 10 Carbon
Pink Diamond 10 Carbon
Yellow Diamond 10 Carbon
Brown Diamond 10 Carbon
Green Diamond 10 Carbon
Blue Diamond 10 Carbon
Ruby 9 Corundum Group
Sapphire 9 Corundum Group
Synthetic Sapphire 9 Synthetic
Synthetic Ruby 9 Synthetic
Alexandrite 8.5 Chrysoberyl Group
Chrysoberyl 8.5 Chrysoberyl Group
Taaffeite 8-8.5 Spinel Group
Red Spinel 8 Spinel Group
Blue Spinel 8 Spinel Group
Pink Spinel 8 Spinel Group
Burmese Spinel 8 Spinel Group
Tanzanian Spinel 8 Spinel Group
Vietnamese Purple Spinel 8 Spinel Group
Spinel 8 Spinel Group
Mahenge Spinel 8 Spinel Group

Some directional weakness

Gem Hardness Mineral Group
Phenakite 7.5-8 Beryllium Group
Paraiba Tourmaline 7-7.5 Tourmaline Group
Tsavorite 7-7.5 Garnet Group
Rubellite 7-7.5 Tourmaline Group
Indicolite 7-7.5 Tourmaline Group
Watermelon Tourmaline 7-7.5 Tourmaline Group
Rhodolite 7-7.5 Garnet Group
Almandine 7-7.5 Garnet Group
Pyrope 7-7.5 Garnet Group
Spessartite 7-7.5 Garnet Group
Grossular 7-7.5 Garnet Group
Uvarovite 7-7.5 Garnet Group
Mali Garnet 7-7.5 Garnet Group
Color-Change Garnet 7-7.5 Garnet Group
Verdelite 7-7.5 Tourmaline Group
Tourmaline 7-7.5 Tourmaline Group
Malaya Garnet 7-7.5 Garnet Group
Achroite 7-7.5 Tourmaline Group
Elbaite 7-7.5 Tourmaline Group
Andradite 6.5-7.5 Garnet Group
Amethyst 7 Quartz Group
Citrine 7 Quartz Group
Rose Quartz 7 Quartz Group
Smoky Quartz 7 Quartz Group
Ametrine 7 Quartz Group
Prasiolite 7 Quartz Group
Milky Quartz 7 Quartz Group
Rock Crystal 7 Quartz Group
Rutilated Quartz 7 Quartz Group
Tourmalinated Quartz 7 Quartz Group
Zircon 6.5-7.5 Zircon Group
Quartz 7 Quartz Group
Garnet 6.5-7.5 Garnet Group
Demantoid 6.5-7 Garnet Group
Clinohumite 6.5-7 Humite Group
Chondrodite 6-6.5 Humite Group

Orientation critical

Gem Hardness Mineral Group
Padparadscha Sapphire 9 Corundum Group
Synthetic Emerald 9 Synthetic
Musgravite 8-8.5 Spinel Group
Emerald 8 Beryl Group
Painite 8 Borate Group
Imperial Topaz 8 Topaz Group
Pink Topaz 8 Topaz Group
Aquamarine 8 Beryl Group
Morganite 8 Beryl Group
Heliodor 8 Beryl Group
Goshenite 8 Beryl Group
Green Beryl 8 Beryl Group
Topaz 8 Topaz Group
Pezzottaite 8 Beryl Group
Blue Topaz 8 Topaz Group
Opaque Emerald 8 Beryl Group
Beryl 8 Beryl Group
Bixbite 7.5–8 Beryl Group
Grandidierite 7.5 Borosilicate Group
Andalusite 7.5 Andalusite Group
Euclase 7.5 Beryllium Group
Iolite 7-7.5 Cordierite Group
Jeremejevite 6.5-7.5 Borosilicate Group
Sillimanite 6.5-7.5 Silicate Group
Serendibite 6.5-7 Borosilicate Group
Hiddenite 6.5-7 Spodumene Group
Diaspore 6.5-7 Oxide Group
Kunzite 6.5-7 Spodumene Group
Peridot 6.5-7 Olivine Group
Spodumene 6.5-7 Spodumene Group
Tanzanite 6-7 Zoisite Group
Zoisite 6-7 Zoisite Group
Kyanite 4-7 (variable) Kyanite Group

Fragile during setting

Gem Hardness Mineral Group
Hambergite 7.5 Borate Group
Danburite 7-7.5 Danburite Group
Kornerupine 6.5-7 Kornerupine Group
Axinite 6.5-7 Borosilicate Group
Vesuvianite 6.5 Sorosilicate Group
Epidote 6-7 Sorosilicate Group
Idocrase 6.5 Sorosilicate Group
Benitoite 6-6.5 Cyclosilicate Group
Moonstone 6-6.5 Feldspar Group
Labradorite 6-6.5 Feldspar Group
Sunstone 6-6.5 Feldspar Group
Amazonite 6-6.5 Feldspar Group
Orthoclase 6-6.5 Feldspar Group
Andesine 6-6.5 Feldspar Group
Oligoclase 6-6.5 Feldspar Group
Prehnite 6-6.5 Phyllosilicate Group
Feldspar 6-6.5 Feldspar Group
Bytownite 6-6.5 Feldspar Group
Petalite 6-6.5 Phyllosilicate Group
Albite 6-6.5 Feldspar Group
Sodalite 5.5-6 Feldspathoid Group
Scapolite 5.5-6 Scapolite Group
Diopside 5.5-6 Pyroxene Group
Hackmanite 5.5-6 Sodalite Group
Hauyne 5.5-6 Sodalite Group
Opaque Hauyne 5.5-6 Sodalite Group
Amblygonite 5.5-6 Phosphate Group
Vayrynenite 5.5 Phosphate Group
Afghanite 5.5 Cancrinite Group
Enstatite 5-6 Pyroxene Group
Hypersthene 5-6 Pyroxene Group
Brazilianite 5.5 Phosphate Group
Pargasite 5-6 Amphibole Group
Apatite 5 Phosphate Group

Extreme cleavage

Gem Hardness Mineral Group
Sapphirine 7.5 Sapphirine Group
Pollucite 6.5-7 Zeolite Group
Cassiterite 6-7 Oxide Group
Tantalite 6-6.5 Tantalite Group
Triplite 5-6 Triphalosilicate Group
Sphene 5-5.5 Titanite Group
Chrome Sphene 5-5.5 Titanite Group
Herderite 5-5.5 Phosphate Group
Stibiotantalite 5-5.5 Tantalate Group
Poudretteite 5 Osumilite Group
Dioptase 5 Cyclosilicate Group
Scheelite 4.5-5 Tungstate Group
Xenotime 4-5 Phosphate Group
Parisite 4.5 Rare Earth Carbonate Group
Bastnasite 4-4.5 Carbonate Group
Smithsonite 4-4.5 Carbonate Group
Rhodochrosite 3.5-4.5 Carbonate Group
Fluorite 4 Halide Group
Sphalerite 3.5-4 Sulfide Group
Malachite 3.5-4 Carbonate Group
Azurite 3.5-4 Carbonate Group
Aragonite 3.5-4 Carbonate Group
Cuprite 3.5-4 Oxide Group
Cerussite 3-3.5 Carbonate Group
Phosphophyllite 3-3.5 Phosphate Group
Calcite 3 Carbonate Group
Erythrite 1.5-2.5 Arsenate Group

Cabochon Preferred

Gem Hardness Mineral Group
Star Sapphire 9 Corundum Group
Star Ruby 9 Corundum Group
Cat's Eye Chrysoberyl 8.5 Chrysoberyl Group
Aventurine 7 Quartz Group
Tiger's Eye 7 Quartz Group
Hawk's Eye 7 Quartz Group
Chalcedony 7 Quartz Group
Agate 7 Quartz Group
Carnelian 7 Quartz Group
Chrysoprase 7 Quartz Group
Onyx 7 Quartz Group
Sardonyx 7 Quartz Group
Bloodstone 7 Quartz Group
Jasper 7 Quartz Group
Jadeite 6.5-7 Pyroxene Group
Nephrite 6-6.5 Amphibole Group
Black Opal 5.5-6.5 Opal Group
Fire Opal 5.5-6.5 Opal Group
Crystal Opal 5.5-6.5 Opal Group
Boulder Opal 5.5-6.5 Opal Group
White Opal 5.5-6.5 Opal Group
Jelly Opal 5.5-6.5 Opal Group
Hyalite 5.5-6.5 Opal Group
Peruvian Opal 5.5-6.5 Opal Group
Sugilite 5.5-6.5 Sugilite Group
Rhodonite 5.5-6.5 Pyroxenoid Group
Opal 5.5-6.5 Opal Group
Hematite 5.5-6.5 Oxide Group
Charoite 5-6 Charoite Group
Lapis Lazuli 5-6 Lazurite Group
Turquoise 5-6 Phosphate Group
Moldavite 5-6 Tektite Group
Larimar 4.5-5 Pectolite Group
Serpentine 2.5-5.5 Serpentine Group
Seraphinite 2-4 Clinochlore Group
Ammolite 1-3 Other Organic Minerals
Lepidolite 1-3 Other Organic Minerals