1. Physical properties are properties that are based on physical, not chemical aspects of the mineral. Hardness of a mineral is a physical property, but what substances the mineral reacts with is a chemical property.

2. Hardness (1-10) (Quantitative) Hardness of a mineral is determined by how tightly packed the atoms making up the mineral are held together. This makes hardness a physical property. No chemical reactions are involved in determining hardness of a mineral and no chemistry is involved in measuring hardness. Soft minerals (<3) have the atoms fairly loosely packed Hard minerals (>7) have the minerals tightly packed Soft minerals can be scratched easily by harder things.

3. Moh’s Hardness Scale (1-10) Soft to hard 1 to 10 1 is softest, 10 is hardest Diamond would be 10 Common tools to use for determining hardness Fingernail 2.5 Copper penny 3.5 Glass plate 5.5 Steel nail 6.5

4. In groups of 3(not exact order) 3 softest minerals are- Gypsum Calcite Talc 3 medium minerals are- O. feldspar Apatite Fluorite 3 hardest minerals are- Quartz Topaz Corundum

6. STREAK The color of a mineral when it is powdered is called the streak of the mineral. Crushing and powdering a mineral eliminates some of the effects of impurities and structural flaws, and is therefore more diagnostic for some minerals than their color. Streak can be determined for any mineral by crushing it with a hammer, but it is more commonly (and less destructively) obtained by rubbing the mineral across the surface of a hard, unglazed porcelain material called a streak plate.surface

7. Streak continued- Sometimes a mineral’s streak matches it’s color. For others, the streak may be quite different from the color, as for example the red-brown streak of hematite, often a gray to silver-gray mineral. The surface of minerals can become discolored due to exposure to air, but the streak will be consistent and thus is reliable as a physical property.

8. Examples of streak *Notice the color differences between the mineral and the streak.

9. Luster is how mineral reflects light The luster of a mineral is the way its surface reflects light. It will be necessary, at least at first, only to distinguish between minerals with a metallic luster and those with one of the non- metallic lusters. Most terms used to describe luster are self-explanatory: metallic, or non-metallic such as earthy, waxy, greasy, vitreous (glassy),describe A metallic luster is a shiny, opaque appearance similar to a bright chrome bumper on an automobile or like a mirror.brightautomobile Other shiny, but somewhat translucent or transparent lusters such as glassy, dull, earthy, and waxy, are grouped as non- metallic.

10. Metallic Luster examples

12. Sub-metallic luster Sometimes determining the luster of a mineral is not so obvious, sometimes there is a little “gray area” in determining luster. The term “sub-metallic” can be used sparingly to describe the luster of minerals that really don’t seem to fit in the metallic/nonmetallic box. CAUTION: USE the sub-metallic description sparingly.

13. Cleavage/Fracture/Crystals

14. Cleavage In mineral terms, cleavage describes how a crystal breaks when subject to stress on a particular plane. If part of a crystal breaks due to stress and the broken piece retains a smooth plane or crystal shape, the mineral has cleavage. A mineral that never produces any crystallized fragments when broken off due to stress has no cleavage. This would be “fracture”.crystalplane Cleavage is measured by two factors: quality and number of sides exhibiting cleavage. Quality of cleavage can be categorized into four qualities:factors Perfect Good Poor None

15. Biotite mica and Muscovite Mica Both show 1 cleavage plane

16. Calcite (left) Halite (right) Both have 3 cleavage planes but notice the subtle differences?

17. Cleavage Images

18. Fracture Fracture is breakage that is not flat. The two main kinds of fracture are conchoidal (shell-shaped, as in quartz) and uneven. Metallic minerals may have a hackly (jagged) fracture. A mineral may have good cleavage in one or two directions but fracture in another direction.