What is a mineral?
A mineral is a:
an orderly crystalline structure
definite chemical composition.
(It's important to know all four bullet points)
What is a rock?
A rock is any solid mass of mineral or mineral-like matter that occurs naturally as part of our planet.
Seven Primary Diagnostic Properties:
- Crystal form: Cube, hexagonal prism, etc.
- Luster: Shiny? Dull?
- Color: Red, green, blue, etc.
- Streak: Scrape color on porcelain plate
- Hardness: Mohs scale Talc < Feldspar < Diamond
- Fracture or cleavage: Angle of crack
- Specific gravity: Density of rock/ density of water
Note about fracture vs. cleavage
Fracture- Break glass -> weird cut, not uniform
Cleavage- Break a mineral -> cleanly, uniformly breaks
Secondary Diagnostic Properties:
Taste, magnetism, malleability, feel, elasticity, smell, chemical reaction to HCl, and double refraction
Top 8 Elements that make up rocks (on Earth)
Know the first two, they make up 70% of all rocks
This has one omission, which is that metamorphic rock may be exposed to MORE heat and pressure, becoming another metamorphic rock.