2. * There are many properties that can be used to identify minerals. * Any one property is not enough to identify minerals.

3. * Color is the most obvious but least dependable property. * Some minerals always have the same color, such as gold. * Others, such as calcite, have a wide range of colors. * Some minerals glow under an ultraviolet light. * These minerals are said to be fluorescent.

4. * Streak * Streak is the color of a crushed mineral powder. mineral what color it leaves. * A mineral is pulled across a streak plate to see what color it leaves. * streak * The color of the streak may be different than the color of the mineral. stays the same * Nearly every mineral has a streak color that stays the same regardless of the color of the mineral. Calcite white * EX. Calcite comes in many colors, but the streak is always white.

5. * Cleavage fracture * Cleavage and fracture describe how a crystal breaks. cleavage * If part of the crystal breaks due to stress and the broken pieces has smooth planes or a crystal shape, the mineral has cleavage. no cleavage. * A mineral that never produces smooth planes when broken has no cleavage. * Fracture cleavage. * Fracture is used to describe the way a mineral breaks if it does not have cleavage. irregular * The broken area will be irregular and jagged.

6. * Luster * Luster is the way the surface of a substance reflects light. * Metallic * Metallic: opaque and reflects light like metals. * Vitreous70% * Vitreous: glassy; applies to about 70% of minerals. * Adamantine * Adamantine: brilliant or diamond-like; high shine. * Silky * Silky: reflect like silk cloth; have fine fibrous structures. * Pearly * Pearly: similar to mother-of-pearl. * Dull * Dull: poor reflectors; minerals have rough, porous textures.

7. * Hardness * Hardness is how well a substance will resist scratching by another substance. * A scale was devised by Friedrich Mohs in 1822. 1 being the softest10 being the hardest * The scale consists of numbers 1-10, with 1 being the softest and 10 being the hardest. mineral * Each number represents a different mineral, with each being harder to scratch than the previous. * Minerals can be between numbers (a mineral could be harder than a three but softer than a 4).