What 6 characteristics is required to identify a mineral
- Naturally occurring
- Crystalline structure
- Physical properties
- Defined chemical composition.
Name the 12 physical properties of minerals
- Color. Streak. Clarity.
- Habit. Luster. Hardness.
- Cleavage & Fracture. Reaction to acid. Striations. Magnetism. Specific Gravity. Tenacity.
What is Streak?
- Color of the powdered mineral.
- Determined by rubbing the mineral on a piece of unglazed porcelain.
What is Clarity?
The way a mineral transmits light.
Name the 3 types of Clarity.
Define a Transparent Clarity.
Mineral is able to transmit light with scattering.
Define a Translucent Clarity.
Mineral diffuses light, so you can not see an object through it.
Define an Opaque Clarity.
Blocks all passage of radiant light.
What is a Habit?
The form or shape that a crystal takes as it grows.
What is Luster?
The way a mineral reflects light.
What are the 3 main classifications of Luster?
What is a Metallic Luster?
Mineral is opaque and reflects light like metal.
What is a Sub-metallic luster?
Mineral is opaque and reflect light well. Thin Splinters or suctions of sub-metallic minerals are translucent.
What is Mohs hardness scale?
1. Talc 2. Gypsum 3. Calcite 4. Fluorite 5. Apatite 6. Feldspar (microline) 7. Quartz 8. Topaz 9. Corundum 10. Diamond
What is Cleavage?
- The breaking or splitting of mineral crystals along planes of weakness.
- A mineral will always have the same cleavage.
What is a Fracture?
A description of the way a mineral tends to break.
Define Excellent Cleavage.
No rough surfaces, a smooth surface.
Define Good cleavage.
Smooth surface, but leave some rough surface.
Define poor cleavage.
The smooth crystal edge is barely visible, since rough surface is dominant.
Broken surface is jagged and rough with no level planes.
what is a splintery fracture?
Fibrous, looks like wood.
what is hackly fracture?
Resembles broken metal. Rough, Jagged, with points.
what is a conchoidal fracture?
Fracture resembles semicircular shell, with a smooth, curved, surface.
What is Tenacity?
The manner in which a mineral resists breakage.
Name the 4 types of Tenacity.
A mineral is liable to fracture with stress.
capable of being flattened into then sheets without cracking.
The ability to cut into pieces.
The ability to deform under stress, and return to original shape.