Minerals: Fracture

When we tested hardness, we were trying to scratch the specimen, not break it. For the next two tests, fracture and cleavage, we will be breaking the specimens. We are not looking at how difficult it is to break them. Instead, we will be looking at how they break, especially at the shape of those broken surfaces. Minerals that break in flat, smooth planes have a property called cleavage, and we will look at those in the next test. Any kind of break that is not cleavage is called fracture, and there are several different kinds.

Minerals: Hardness

One of the most important tests for identifying a mineral is determining its hardness. After we determine the luster of a mineral, hardness is the test we use to narrow down the possible choices.



This is Carlsbad Caverns. What are the main chemicals involved in the formation of all of those beautiful, flowstone structures?


Nancy and I found these geologic wonders in a dry stream on our way to Bryce Canyon. What are they?

Is That Really a Diamond?

It is amazing how many things people commonly think of as scientific fact which really are false. For example, vultures do not circle over a dying animal. Raindrops are round, not teardrop shaped. One of my favorite misconceptions is the idea that you can identify a diamond because it will cut glass. For this experiment you will need:

Minerals: Cleavage

Minerals that break in flat, smooth planes are said to have cleavage. Like many things in science, this is much easier to understand if you actually see it, so lets do an experiment.

You will need: