Crystals, Gems, Minerals or Rocks

Question 1

Crystal

Answer 1

A mineral that has a crystalline interior structure. Agate, which is a hexagonal crystal, is also a mineral and a rock.

Question 2

Gem

Answer 2

A cut and polished crystal, mineral, or rock. A cut diamond (which is a mineral, crystal, and rock) is also a gem or gemstone. Amber and pearls are organic substances that are considered gemstones, but they are not crystals, minerals, or rocks.

Question 3

Mineral

Answer 3

A naturally occurring substance with specific chemical composition and a highly ordered structure that may or may not be crystalline. Opal is a mineral that does not have a crystalline structure; it’s a gemstone and a rock but not a true crystal.

Question 4

Rock

Answer 4

A combination, or aggregate, of minerals. Marble, which is made up of multiple minerals, is a metamorphic rock—a rock that has been subjected to heat and pressure over time.