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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.
Amethyst Galleries
Amethyst Galleries: Mineral Gallery: The Color of Minerals
This resource provides information about the color of minerals.
San Diego Natural History Museum
San Diego Natural History Museum: Mineral Matters: Color
Don't be fooled! While color is one way to identify a mineral, it can often be misleading. Quartz is one example of a mineral that can change colors depending on its chemical make-up.