Unit one quiz Flashcards
Name one mineral that has perfect cleavage in one direction?
Micas
What is the colour of hematite’s (Fe2O3) streak?3
reddish brown
What is the only crystal system with four axes?
Hexagonal
What is the term used to describe an igneous rock with large, well-formed crystals in a very fine-grained matrix (groundmass)
Porphyritic
If a sedimentary rock is composed of fragments/clasts of pre-existing rocks, what type of sedimentary rock is it?
Clastic
if a rock is similar to a breccia, but contains rounded clasts instead of angular clasts, what is the name of this rock?
Conglomerate
Coquina represents a biogenic sedimentary rock formed from accumulation of what type of material?
sand size fossil debris
What is the hardest mineral on the Moh’s scale of hardness, with a hardness of 10?
Diamond
What is the hardness of the mineral corundum?
9
What is the softest mineral on the Moh’s scale of hardness, with a hardness of 1?
Talc
What is the most common chemical group of minerals?
Silicates
List the most highly-abundant elements in the Earth’s crust?
Oxygen
Which rock type forms through the crystallization of magma?
Igneous rock
Which rock type forms through the application of heat and/or pressure to pre-existing rocks?
Metamorphic rocks
What characteristic texture of metamorphic rocks is formed by the alignment of platy mineral grains, such as micas
Planar foliation
Which type of metamorphism is large-scale and often occurs during the formation of mountain belts
regional metamorphism
Define the term “cleavage”. Can it be used to describe the crystal faces of a mineral?
the tendency of a mineral to break along certain planes to make smooth surfaces
Can minerals can have different hardnesses on different crystal faces?
minerals hardness varies from crystal face to crystal face
What is more reliable in mineral identification, the colour of a mineral or the colour of its streak?
streak
What is the luster of the mineral quartz?
scale 7, streak white
What is the luster of the mineral galena?
Metallic
If a mineral has three axes of symmetry of equal length, all 90° to one another, in which crystal system does it belong?
Isometric