Introduction to Minerals Aim: What are minerals?

Do Now: Why do we take our vitamins and minerals instead of vitamins and rocks?

I. What’s the difference? Mineral- a pure substance, found on the earth that occurs in nature, that is inorganic (non-living), and homogeneous (uniform). Rock- is a substance that is or was a natural part of the solid earth.

II. Testing Minerals Cleavage- refers to the tendency of some minerals to break along smooth, flat planes. 1. Fracture- (opposite of cleavage) when minerals break and don’t have a defined shape, the atomic arrangement of atoms is not in a regular pattern.

Properties Continued Color- some minerals have their own unique color Sulfur=yellow Olivine=green Garnet=red

Why do you think it is not good to only use color? Different minerals may have the same color. Talc Gypsum Quartz Calcite

These are all the mineral Calcite. One mineral can come in many colors.

Properties Continued… C. Streak Test- color of the powder left behind on a streak plate (ceramic plate)

Streak Continued Pyrite with its green-black streak Hematite with its red-brown streak

Properties Continued… D. Luster- how light reflects off the mineral. There are two main types of luster: Metallic- Non-Metallic- Looks like metal Doesn’t look like a (ex. Tinfoil) metal.

Properties Continued… E. Moh’s Hardness Scale- resistance to being scratched. Hardness depends on how tightly packed the molecules are in the mineral. Scale of 1-10, 10 (Diamond) is the hardest.

Loose arrangement of atoms= Soft Mineral

Tight arrangement of atoms=Hard Mineral

Properties Continued… F. Hydrochloric (HCL) Acid Test- when HCL is applied to calcite it will fizz on contact. HCl

The only mineral in a solid rock form, that has this characteristic is calcite.

HCL on Calcite HCL on Calcite