minerals

Minerals are natural, solid substances found in the Earth's rocks, each with its own fixed chemical composition.

• Most minerals are actually compounds made of more than one element — quartz, calcite, mica, pyroxene, and olivine are common examples found in rocks all around us.
• A smaller group, called native minerals, are pure elements rather than compounds — gold, silver, and copper among the metals, sulfur and carbon among the non-metals.
• Minerals aren't just geological samples; everyday materials come straight from them — cement is made from calcite, quartz, alumina, and iron oxide, while talcum powder comes from the mineral talc.
• Because each mineral has a fixed composition, identifying an unknown rock often comes down to comparing its minerals against known ones, sometimes just by appearance under a magnifying glass or microscope.