FINALS Day 2 - Petrology Flashcards
Acanthite is an ore mineral of __________.
A. Antimony
B. Silver
C. Titanium
D. Nickel
B. Silver
Chemical formula of Acanthite.
Ag2S
The following minerals are copper-bearing, EXCEPT ________.
A. Malachite
B. Digenite
C. Olivenite
D. Lepidocrocite
D. Lepidocrocite
Chemical formula of Lepidocrocite
FeO(OH)
Which of the following ore minerals is a carbonate?
A. Lepidocrocite
B. Scorodite
C. Clinoclase
D. Smithsonite
D. Smithsonite
Chemical formula of Smithsonite
ZnCO3
The following metals are found in the chemical formula of stannite, EXCEPT:
A. Sb
B. Sn
C. Cu
D. Fe
A. Sb
Chemical formula of Stannite
Cu2FeSnS4
Which mineral-element pair is correct?
A. Annabergite – As
B. Clinoclase – Sb
C. Chrysocolla – Cu
D. Stibnite - Sb
C. Chrysocolla – Cu
Chemical formula of Chrysocolla
(Cu,Al)2H2Si2O5(OH)4·nH2O
Chemical formula of Azurite
Cu3(OH)2(CO3)2
Chemical formula of Siderite
FeCO3
Chemical formula of Ilmenite
FeTiO3
Chemical formula of Digenite
Cu9S5
Chemical formula of Stibnite
Sb2S3
A microcrystalline texture formed by the devitrification of the ground-mass of acid extrusive rocks.
A. Hyalopilitic
B. Felsitic
C. Intersertal
D. Spinifex
B. Felsitic
In an ophitic texture, plagioclase is enclosed by _________.
A. Quartz
B. Biotite
C. Hornblende
D. Pyroxene
D. Pyroxene
___________ describes the layered or banded texture in explosive volcanic rocks. It is often caused by the compaction and flattening of glass shards and pumice fragments.
Eutaxitic Texture
Eutaxitic texture is commonly found in ___________.
A. Ignimbrites
B. Komatiites
C. Amygdaloidal rocks
D. Dolerite
A. Ignimbrites
Spinifex texture is commonly found in _________.
A. Dolerite
B. Gabbros
C. Granite
D. Komatiite
D. Komatiite
These are gas bubbles or vesicles that are infilled with a different secondary mineral.
Amygdules
This texture often results from resorption of quartz by the melt due to ascending and decompression or due to magma mixing.
Embayed Texture
In eutaxitic texture, pumice fragments are compacted into dark, glassy pancake shapes called _________.
Fiamme
Volcanic glass is unstable and tends to change spontaneously or devitrify from the glassy to the crystalline state. This is why ancient glasses are very rare, and most glassy rocks are of _______ age, or less than _________ years old.
Paleogene; 65 myo
It is a porphyritic texture in which phenocrysts are clustered into aggregates called crystal clots.
Glomerophyric (Glomeroporphyritic)
Glomerophyric textures form by a process known as _________, which is the accumulation of crystals by surface tension and fixing by interpenetration due to crystal growth.
Synneusis
This is a texture of volcanic rocks in which the groundmass consists of small microlites of feldspar that are sub-parallel to each other and are embedded in glass.
Hyalopilitic
The ratio of crystals to glass in this texture is greater than 3:5.
Hypocrystalline
____________ rocks were generally cooled rapidly, which inhibits growth rate and nucleation of crystals.
Holohyaline
This is the texture of an igneous rock that has crystalline components in a glassy groundmass, with a ratio of crystals to glass between 3:5 and 1:7.
Hypohyaline
This texture occurs when a crystal occupies the angular space between at least two larger crystals.
Intergranular
This texture occurs when the angular spaces between larger crystals is occupied by glass, or glass and small crystals.
Intersertal
This is a common structure of hydrated mineral in volcanic rocks such as biotite or amphiboles. It is also often described as a devolatilization process.
Opacitic Rim or Reaction Rim
A texture is ophitic when plagioclase laths are enclosed by _________ or ___________.
Pyroxene or Olivine