The Study of Minerals Flashcards
What is a mineral?
A naturally occurring, inorganic solid with an orderly internal arrangement of atoms (called crystalline structure) and a definite, but not fixed, chemical composition.
What are rock forming minerals?
The abundant minerals that often occur with each other in the rocks of Earths crust.
Luster is a primary optical property which is the ability to transmit :
Light, color, and streak
What are the primary physical properties of a mineral?
Luster, hardness, crystal form, cleavage or fracture, and specific gravity.
What are the secondary (or “special”) properties of a mineral?
Magnetism, taste, feel, striations, tenacity, and the reaction with dilute hydrochloric acid.
Define luster :
Luster descibes the manner in which light is reflected from the surface of a mineral.
What is metallic luster?
Any mineral that shines with a metal-like appearance is said to have a metallic luster.
What is nonmetallic luster?
Minerals that do not have a metallic luster, and may have one of a variety of lusters that include virteous (glassy), pearly, or earthy (dull, like soil or concrete) are said to have a nonmetallic luster.
**The ability of a mineral to transmit light can be descibed as either : **
Opaque, translucent, or transparent
**Define opaque : **
A mineral is opaque when no light is transmitted.
Define translucent :
A mineral is translucent when light but not an image is transmitted.
**Define transparent : **
**A mineral is transparent when an image is visible through the mineral. **
Which physical property of minerals is the least reliable and why?
Color, because it can be manipulated by slight impurities.
**Define streak : **
The streak of a mineral is the color of the fine powder of a mineral obtained by rubbing a corner across a piece of unglazed porcelain - called a streak plate.
What is the most reliable property of a mineral?
Streak
**Define hardness : **
Hardness is one of the most useful diagnostic properties of a mineral and is a measure of the resistance of a mineral to abrasion or scratching.
**Define crystal form : **
Crystal form is the external appearance or shape of a mineral that results from the internal, orderly arrangement of atoms.
Most _______ ________ consist of crystals.
inorganic substances
**Crystal faces are the : **
Crystal faces are the flat external surfaces on a crystal.
What are the sample minerals for the Mohs scale?
- Diamond
- Corundum
- Topaz
- Quartz
- Orthoclase
- Apatite
- Fluorite
- Calcite
- Gypsum
- Talc
**Define cleavage : **
Cleavage is the tendency of some minerals to break along regular planes of weak bonding between atoms in the internal crystalline structure.
What are cleavage planes?
Cleavage planes are smooth, flat surfaces produced when minerals that exhibit cleavage are broken.
What are directions of cleavage?
Directions of cleavage are the number of different sets of planes that form the surfaces of a mineral crystal when it cleaves.
How is cleavage determined?
Cleavage is determined by the band that holds atoms together, while crystal form results from the internal, orderly arrangement of the atoms.
**Define fracture : **
**Fracture is when a mineral is broken and does not exhibit cleavage. **
What are the three types of fracturing?
Irregular, splintery, or conchoidal (smooth curved surfaces resembling broken glass).
**Define specific gravity : **
Specific gravity is a number that represents the ratio of the weight of a mineral to the weight of an equal volume of water.
**Define magnetism : **
Magnetism is a characteristic of minerals, such as Magnetite, that have high iron content and are attracted by a magnet.
**Define striations : **
Striations are closely spaced, fine lines on the crystal faces of some minerals.
Define tenacity :
Tenacity is the manner in which a substance resists breaking.
What are carbonate minerals?
Carbonate minerals are a group of minerals that release carbon dioxide when exposed to a drop of dilute hydrochloric acid.
