Mineral shape
Before describing shape it is important to distinguish whether you are looking at a single crystal or at this.
What is aggregate?
Evaluated using a scratching test.
What is hardness?
Earth mantle's most abundant
What is olivine?
Easy to assess, but be aware, this property can be deceiving.
What is mineral color?
A unitless measure of how much speed of light is slowed down when it passes through a transparent material.
What is index of refraction?
What is habit?
10 reference minerals arranged from soft to hard.
What is the Moh's scale?
What is quartz?
Subjective property, described to be silky or greasy, for example.
What is luster?
The Becke line test is used to assess whether this is positive or negative, in PPL.
What is relief?
The opposite of anhedral.
What is euhedral?
What is 8?
What is biotite?
It describes how much you can see through a mineral.
What is transparency?
Organizes the colors of interference and correlates between light retardation, sample thickness, and birefringence.
What is the Michel Levy chart?
Equally developed along axes x, y, and z.
What is equant?
Number 5 on the Moh's scale
What is apatite?
Obviously birefringent in large, clear cleaved crystals
What is calcite?
With this type of luster a mineral shines like a diamond.
What is adamantine?
Lines needed to measure the extinction angle of a mineral under polarizing microscope.
What are lines of cleavage or other crystallographic directions?
Shaped like a needle.
What is acicular?
It controls hardness, cleavage, and shape, but it does not influence color and luster as much as the chemical composition of minerals.
What is the atomic structure?
Potassium feldspar with characteristic tartan (plaid) polysynthetic twinning.
What is microcline?
Metallic minerals appear to be _______ in PPL.
What is opaque?
Minerals in this crystallographic system are optically isotropic.
What is isometric (or cubic)?