Many minerals are coveted around the world for their striking beauty, rarity, and gem quality. But what is a mineral?
A mineral is a solid, naturally occurring, inorganic substance that generally forms crystals. They are identified and described according to their physical properties of:
- Cleavage: The tendency of a mineral to break (cleave) along weak planes.
- Color: Most minerals have a distinct color while others are variable in color.
- Hardness: A measure of a mineral's resistance to scratching. This is measured by scratching it against another substance of known hardness on the Mohs Hardness Scale
- Luster: The reflection of light from the surface of a mineral, described by its quality and intensity. Luster is described as metallic, glassy, dull, earthy, etc.
- Streak: refers to the color of the residue left by scratching a mineral on a tile of unglazed porcelain, like a piece of chalk.
- Specific gravity: the ratio of the density of a mineral to an equal volume of water
To many, the National Park System is one of America's favorite mineral collections which can be viewed in the various rock formations and features around the country.
Natural objects, such as rocks and minerals, contribute to the beauty and wonderment of the National Parks and should be left, as they were found, so that others can experience a sense of discovery.
- Nonsilicate minerals: A mineral without silicon (Si).
- Silicate: Refers to the chemical unit silicon tetroxide, SiO4, the fundamental building block of silicate minerals. Silicate minerals make up most rocks we see at the Earth's surface.