What causes phosphorescence?
This phosphorescence is usually caused by algae suspended in the water. Much like fireflies flitting through the air, the algae (of a wide variety of species) emit a glow whenever they are jostled. Sometimes that's caused by the tides rolling in and out.
Therefore, not all gemstones are minerals. For example, amber is solidified tree resin, so it is not a mineral. Gemstones can be classified as either amorphous or crystalline. Amorphous gemstones have no orderly internal atomic structure and no naturally occurring shape.
- Minerals occur naturally in the earth's crust and are defined as inorganic solids that have characteristic chemical composition and crystalline structures. A gemstone or gem is a piece of mineral crystal, which, in cut and polished form, is used to make jewelry or other adornments.
- Minerals can be found throughout the world in the earth's crust but usually in such small amounts that they not worth extracting. Only with the help of certain geological processes are minerals concentrated into economically viable deposits. Mineral deposits can only be extracted where they are found.
- A rock is a solid, inorganic, naturally-formed substance without a particular atomic structure or chemical composition. It's probably easier to just remember that rocks are made up of two or more minerals.
Updated: 17th October 2019