10 help me with this i pay right away it earth science 6th grade

Assignment: Mineral Identification
Investigation

Mineral Identification Data Table
Sample Number	Color	Cleavage or Fracture	Luster
25
26
27
13
7
23

Analysis

Sample
7:  

Sample
13:  

Sample
23:  

Sample
25:  

Sample
26:  

Sample
27:  

Questions

1. 
Which
mineral above would be the most difficult to scratch?

2. 
Give
two examples of minerals that have a property in common.

3. 
Could
you have identified any of the minerals after having described only a few,
rather than all, of the properties you tested? If so, give an example.

4. 
Why
is it still a good idea to test more properties than might be necessary?