Crystal Growth How does the change in temperature affect the sizes of and amount of crystals present? Special crystal landmarks in Mexico: How to identify if something is a mineral? Key properties of classifying minerals. A Substance That Is: Naturally occurring Inorganic Solid Consistent Chemical Make-Up (not created by any organisms) (has a repeating chemical pattern) Naturally occurring means that people did not make it. Steel is not a mineral because it is an alloy produced by people. Inorganic means that the substance is not made by an organism. Wood and pearls are made by organisms and thus are not minerals. Solid means that it is not a liquid or a gas at standard temperature and pressure. Consistent Chemical Make-Up means that all occurrences of that mineral have the same chemical composition, and the atoms in the mineral are arranged in a organized and repeating pattern. There are five main properties geologists use to classify a mineral. These are: Colour Hardness (the resistance to scratching) Lustre (the shine or reflection of light) Cleavage (the direction in which it breaks) Density (the mass per unit volume) Why is colour not the best way to determine the identity of a mineral? What is the hardest mineral in the world? Using one of the five main properties, explain why a bucket filled with gold may be heavier than a bucket filled with quartz. Don’t get tricked by this special gold-coloured mineral: A lot of minerals have the same colour as each other, and colour is easily changed by dust/dirt or paints. Moh’s Scale of Mineral Hardness Non-linear scale Invented in 1812 Still relevant as a rough comparison tool Density is how much matter is in the mineral. It is measured by the substance’s mass per unit volume For minerals you will see the units g/cm3 or g/cc which means grams per cubic centimetre.