Identifying Rocks – L

To try to identify your rock, you should look at some characteristics and qualities.  Here are some characteristics to look for.

1) What color is your rock or mineral?

Different rocks and minerals are composed of different materials.  Rocks and minerals can be found in a lot different colors.  It is important to think about where you found the work though.  Conditions like weather and contact with other materials can change the color of rocks and minerals.  Color CAN be used to help identify a rock, but it is not the best way.

2)  Is your rock/mineral smooth? bumpy?  rough?

These are words you would use to describe the texture of your rock.  Some rocks, like pumice, are rough and full of holes.

3) Is your rock heavy or light?

Comparing the weight and density of rocks can be helpful in identification.  Some rocks/minerals, like gold and silver, are very heavy.  Other rocks, like pumice, are so light they can float!

4)  Is your rock/mineral shiny?

The way the rock or mineral reflects light is referred to as LUSTER.  Is the surface very reflective (like a metal)?  Is it shiny like glass?  Does it have a pearl-like appearance?  Maybe it is dull and does not reflect light at all?

5) How hard is your rock/mineral?

You can test this by comparing how your rock scratches other surfaces.  (Be careful what you test this on!)  You can also explain how easy it is to scratch your rock/mineral.    There is a scale called the Mohs Hardness Scale that compares the hardness of common rocks/minerals. You can look at this one for reference.

6) If you rub the rock/mineral across a surface like a concrete sidewalk, what mark does it make?

The mark or color left behind when you rub the rock/mineral against a rough surface is called the STREAK.

7) Describe the way your rock/mineral breaks.

Some rocks or minerals will break in sheets.  Some break into chunks like cubes.  Some will break leaving jagged edges.  The word used for this characteristic is CLEAVAGE.

 

These are the basic characteristics to look at and record about your rock.  There are other characteristics scientists look at when studying rocks and minerals. Scientists might record the way the rock/mineral forms crystals.  Or they might look at some unusual characteristics like magnetism or odor!  Did you know there are rocks/minerals that can smell like rotten eggs?  Rocks that have sulfur in them will be stinky when broken or rubbed.