Answer:
The Mohs Scale of Hardness consists of 10 classifications, 1 being the softest and up to 10 being the hardest. The diamond is the hardest and is rated 10. The following, is a partial listing of stones and their hardness classification:
1, Talc and Graphite
Can be scratched with a fingernail and by any stone and is rated at 2+
2, Gypsum, Bismuth, Lepidolite , and Chlorite
Can be scratched with a fingernail and any stone and is rated 3+
3, Calcite, Celestite and Barite
Can be scratched with a knife and any stone and is rated 4+
4, Flourite, Malachite and Platinum
Can be scratched with a knife and any stone rated 5+. And will scratch any stone rated 3-.
5, Apatite, Dioptase
Can be scratched with a knife and any stone rated 6+. And will scratch any stone rated 4-
6, Feldspar , Pyrite, Amazonite, Hematite
Can be scratched with a knife and any stone rated 7+. And will scratch any stone rated 5-.
6, Quartz, Tourmaline
Will scratch glass and any stone rated 6-. And can be scratched by stones 8+.
7, Topaz, Spinel
Will scratch glass and any stone rated 7-. And can be scratched by stones 9-10.
9, Corundum (ruby, sapphire)
Will scratch glass and any stone rated 8-. And can be scratched by diamond.
10, Diamond
Will scratch glass and all stones 1-9