Water: Mineral information and picture guide

About

Water is not classified as a mineral, since it lacks a crystal structure being that it is in a liquid form. Many scientific groups and references, including the acclaimed Dana's System of Mineralogy, categorize mineraloids such as Opal and Mercury together with the "true" minerals. However, virtually all mineral reference guides, including Dana's, exclude water from being classified as a mineral. (When water solidifies and turns into Ice, however, it is considered a mineral by all accounts.) We have included water in thus guide for the purpose of delineating its properties so that it can be compared to the true minerals. Water and Mercury are the only two naturally occurring, inorganic substances with a definitive chemical formula that occur in a liquid state at normal temperatures.

Water covers more than 3/4 of the earth's surface, and is its most common and vital resource. It is a major solvent, dissolving more substances than any other liquid. For this reason, water is almost always impure.

Crystal Forms & Aggregates

Water is in a liquid state, and therefore lacking any crystalline form.

Other ID Marks

1) Occurs in a liquid state.
2) Freezes at 32º F (0º C) and boils at 212º F (100º C).
3) When salt impurities are present, water is an electrical conductor.

Complex Tests

Water is unique in that instead of contracting when it solidifies, like almost all matter, it expands upon freezing, and reaches its maximum density at 39° F (4° C). Antimony also exhibits this strange property.

Environment

Water occurs in large and small bodies still bodies of water (oceans, lakes, ponds, swamps), in moving streams, rivers, and springs, as raindrops, in puddles, as dew droplets, etc.