Ms. Hartnett's Earth Science1 Minerals A mineral is a naturally occurring, inorganic solid with distinct physical and chemical properties. Facts about minerals: 1.All minerals are composed of elements (substances made of only one atom). 2.Minerals are homogeneous (they are the same throughout). 3. Most rocks have a number of minerals in common. In other words, there are hundreds of minerals, but only 12 are common and are found in different proportions in different rocks.

Ms. Hartnett's Earth Science2 There are 7 properties that are used in identifying minerals: 1.Hardness – a minerals resistance to being scratched. This is based on Moh’s Scale of Hardness which goes from to is the softest and 10 is the hardest. What mineral has a hardness of 10?________________ 2.Luster – the way a minerals surface reflects light. It is either said to be metallic or non-metallic? 3.Streak – the color of the powdered form of a mineral. The mineral is rubbed against a porcelain plate. 4.Cleavage – the tendency of a mineral to break along planes of internal atomic weakness (how it looks when it breaks). 5.Specific Gravity – density of the mineral 6.Crystal Shape – the shape of a mineral, after it forms. 7.Color – this is the least useful and most unreliable of all of the properties to use.

Ms. Hartnett's Earth Science3