Other
Minerals by Physical and Optical Properties
Over 4,700 mineral species descriptions include HTML-linked mineral tables by physical and optical properties of all known valid mineral species.
San Diego Natural History Museum
San Diego Natural History Museum: Mineral Matters: Hardness
Identifying a mineral by hardness? This website explains how to use the Mohs' hardness scale and provides examples.
James Madison University
James Madison University: Mineral Hardness and Cleavage
An explanation of the Mohs Hardness scale is followed by illustrations of crystal structures and cleavage.
Scholastic
Scholastic: Study Jams! Science: Landforms, Rocks & Minerals: Minerals
A slideshow and a short multiple-choice quiz on the topic of minerals and how to identify them by their properties.
![Indiana University Bloomington: Mohs Hardness Scale [Pdf] Graphic](https://d15y2dacu3jp90.cloudfront.net/images/attachment_defaults/resource/large/FPO-knovation.png "Indiana University Bloomington: Mohs Hardness Scale [Pdf] Graphic")
Indiana University
Indiana University Bloomington: Mohs Hardness Scale [Pdf]
A chart of Mohs hardness scale with pictures of minerals at each level of hardness.