Physical Test

You will often see people post a photograph of a specimen and ask "What is it?" and people will respond: 

• Quartz because it is clear or whitish 

• Calcite because is it whitish or yellowish and opaque

• Fluorite because it is blueish or purplish

BUT I can show you samples of each of those minerals that met those description.

You have to have physical properties of the specimen to correctly identify and support the identification.  The following are some useful one that can be done by a hobbyist.  They are listed in the order I personally find useful and easy (click the link for more information):

1. Hardness on the Mohs hardness scale.

2. Crystal habit if present.

3. Reaction with diluted hydrochloric acid.

4. Fracture.

5. Streak color (the color of the powder of the specimen)

6. Cleavage (how the specimen breaks)

7. Luster (how it looks.  Not a physical test but more of a subjective option)

8. Specific Gravity aka density.  Useful but harder to get a accurate value.

You then can use a mineral guide to find possible minerals.  Not in the age of the internet you can use a site like the advance search of Mindat.