oxides pt 1 Flashcards
(38 cards)
1
Q
in general how do oxides occur?
A
- as accessory minerals in igneous and metamorphic rocks
- as detrital grains in sediments
2
Q
cuprite formula
A
Cu2O
3
Q
cuprite crystal form
A
- isometric: cube, octhedron, dodecahedron
4
Q
cuprite hardness
A
3.5 to 4
5
Q
cuprite specific gravity
A
6.1
6
Q
cuprite color
A
- metallic-adamantine
- various shades of red
- brownish red streak
7
Q
ruby red transparent crystal variety of cuprite
A
ruby copper
8
Q
cuprite occurrence
A
- supergene mineral in oxidized portions in copper deposits
- assoc with limonite, secondary copper minerals
9
Q
cuprite remarks
A
- red color, isometric, high luster, brown streak and assoc with limonite
10
Q
corundum formula
A
Al2O3
11
Q
corundum crystal form
A
- common prismatic/tabular hexagonal crystals
- hexagonal dipyramids, rounded in barrel shapes with deep horizontal striations
- usually rudely crystallized, massive fine or coarse
12
Q
corundum cleavage
A
none. parting on 0001 and 10 1 1
13
Q
corundum hardness
A
9, may alter to mica (dapat fresh)
14
Q
corundum specific gravity
A
4.02
15
Q
corundum color
A
- adamantine to vitreous transparent to translucent
- shades of brown pink blue
- any color or colorness
16
Q
what is red corundum
A
ruby
17
Q
what is gem corundum of any color
A
sapphire
18
Q
corundum occurrence
A
- common accessory in some metamorphic rocks: limestone, mica schist, gneiss
- in SiO2 poor igneous rocks: syenites and nepheline syenites
- as rolled pebbles in detrital soil and stream sands
19
Q
corundum remarks
A
great hardness, high luster, parting and specific gravity
20
Q
hematite formula
A
Fe2O3
21
Q
hematite crystal form
A
- crystals: usually thick to thin tabular on 0001 with hexagonal outline
- thin plates grouped in rosettes
- botryoidal to reniform in radiating structures
- may also be micaceous and foliated also earthy
22
Q
hematite is aka?
A
kidney ore
23
Q
term for the micaceous and foliated hematite
A
specular hematite
24
Q
hematite cleavage
A
parting on 10 1 and 0001
25
hematite hardness
5.5 to 6.5 (crystals)
26
hematite specific gravity
5.26 (crystals)
27
hematite color
- reddish brown to black
- dull in earthy
- light to dark red streak
28
platy and metallic variety of hematite
specularite
29
red earthy variety of hematite
red ochre
30
hematite occurrence
- accessory mineral in many rocks
- most abundant iron ore mineral in precambrian banded iron formations
- sublimation product in volcanic rocks
- accessory constituent in granite
- in metamorphic assemblages
- minor constituent of red sandstone, as cementing material binding quartz and grains together
- in oolitic sedimentary iron deposits
31
ilmenite formula
FeTiO3
32
ilmenite crystal form
- massive and compact
- in grains or as sand
33
ilmenite hardness
5.5 to 6
34
ilmenite specific gravity
4.7
35
ilmenite color
- metallic to submetallic opaque
- iron black with metallic to submetallic luster
- brownish red streak
36
ilmenite occurrence
- common accessory in igneous rocks
- large masses in gabbro, diorites and anorthosites
- commonly assoc with magnetite
- as constituent of black sand, assoc with magnetite, rutile and zircon
37
how to distinguish ilmenite from hematite
hema has light to dark red streak, ilmenite has black to brownish red streak
38
how to distinguish ilmenite from magnetite
hema is not strongly magnetic
