Moh's Scale of Hardness for Common Gemstones
Agate = 7
Alexandrite = 8.5
Amber = 2 to 2.5
Amethyst = 7
Apatite = 5
Aquamarine = 7.5 to 8
Aventurine = 7
Bloodstone = 7
Chalcedony = 7
Charoite = 7 (but chips and cracks easily)
Chrysoberyl = 8.5
Citrine = 7
Coral = 3.5 to 4
Cubic zirconia = 8.5
Diopside = 5.5 to 6.5
Fluorite = 4
Garnet = 7 to 7.5
Hematite = 5 to 6.5
Iolite = 7 to 7.5
Jade = 6.5 to 7
Jasper = 7
Kunzite = 6.5 to 7.5
Lapis lazuli = 5 to 6
Malachite = 3.5 to 4.5
Moonstone = 6 to 6.5
Morganite = 7.5 to 8
Obsidian = 5 to 6
Onyx = 7
Opal = 5.5 to 6.5
Pearl = 2.5 to 4.5
Quartz = 7
Rhodochrosite = 3.5 to 4
Sardonyx = 7
Sodalite = 5.5 to 6
Spinel = 7.5 to 8
Tanzanite = 8.5
Topaz = 8
Tourmaline = 7 to 7.5
Turquoise = 5 to 6