OXIDES

Question 1

Cu2O

Answer 1

Cuprite

Question 2

Commonly in isometric crystals that show cube, octahedron, and dodecahedron and combinations thereof.

Answer 2

Cuprite crystal form

Question 3

What is the hardness of cuprite?

Answer 3

3 1/2 -4

Question 4

What is the specific gravity of cuprite?

Answer 4

6.1

Question 5

What is the color of cuprite?

Answer 5

Various shades of red; ruby red in transparent crystals, called “ruby copper.”

Question 6

Found, as a supergene mineral, in the oxidized portions of copper deposits, associated with limonite and secondary copper minerals such as native copper, malachite, azurite, and chrysocolla.

Answer 6

Cuprite

Question 7

Al2O3

Answer 7

Corundum

Question 8

Prismatic or tabular hexagonal crystals are common. May display hexagonal dipyramids that are rounded into barrel shapes with deep horizontal striations.

Answer 8

Crystal form of corundum

Question 9

What is the cleavage of corundum?

Answer 9

Only parting on {0001} and {10\bar1 1}

Question 10

Hardness of corundum?

Answer 10

9

Question 11

What is the specific gravity of corundum?

Answer 11

4.02

Question 12

What is the usual color of corundum

Answer 12

Usually some shade of brown, pink, or blue; but may be colorless or any color.

Question 13

Red gem corundum

Answer 13

ruby

Question 14

Gem corundum of any other color

Answer 14

sapphire

Question 15

Black granular corundum intimately mixed with magnetite and hematite.

Answer 15

emery

Question 16

A common accessory mineral in some metamorphic rocks, such as crystalline limestone, mica schist, or gneiss. Also present in SiO2– poor igneous rocks such as syenites and nepheline syenites.

Answer 16

corundum

Question 17

Fe2O3

Answer 17

Hematite

Question 18

If in crystals, they are usually thick- to thin tabular on {0001} with hexagonal outline. Thin plates may be grouped in rosettes.

Answer 18

crystal form of hematite

Question 19

May also be micaceous and foliated and referred to as ______ hematite

Answer 19

specular

Question 20

What is the cleavage of hematite?

Answer 20

Parting on { 10bar1 1} and {0001}

Question 21

What is the hardness of hematite?

Answer 21

5 1/2 - 6 1/2

Question 22

What is the specific gravity of hematite?

Answer 22

5.26 (for crystals)

Question 23

What is the usual color of hematite?

Answer 23

Reddish brown to black

Question 24

Red earthy variety of hematite?

Answer 24

red ocher

Question 25

Platy and metallic variety of hematite?

Answer 25

specularite

Question 26

An accessory constituent of many rock types and the most abundant iron ore mineral in Precambrian banded iron-formations. It may occur as a sublimation product in volcanic rocks and as an accessory constituent in granites.

Answer 26

occurence of hematite

Question 27

FeTiO3

Answer 27

ilmenite

Question 28

Most commonly massive and compact. Also in grains or as sand.

Answer 28

crystal form of ilmenite

Question 29

What is the hardness of ilmenite?

Answer 29

5 1/2 - 6

Question 30

What is the specific gravity of ilmenite?

Answer 30

4.7

Question 31

What is the color of ilmenite?

Answer 31

Iron black with metallic to submetallic luster.

Question 32

A common accessory in igneous rocks. May occur as large masses in gabbros, diorites, and anorthosites, commonly associated with magnetite.

Answer 32

occurrence of ilmenite

Question 33

TiO2

Answer 33

Rutile

Question 34

Commonly in tetragonal, prismatic crystals with dipyramid terminations and vertically striated prism faces.

Answer 34

crystal form of rutile

Question 35

What is the cleavage of rutile?

Answer 35

Prismatic {110} distinct

Question 36

What is the hardness of rutile?

Answer 36

6-6 1/2

Question 37

What is the specific gravity of rutile?

Answer 37

4.18-4.25

Question 38

What is the color of rutile?

Answer 38

Red, reddish brown to black. Streak pale brown.

Question 39

Found in granite, granite pegmatite, mica schist, gneiss, metamorphic limestone, and dolomite. May be included in quartz and micas as fine-grained slender crystals.

Answer 39

occurrence of rutile

Question 40

MnO2

Answer 40

pyrolusite

Question 41

Usually in radiating fibers or columns. Also granular massive; often in reniform coats and dendritic shapes finely overgrown with other Mn-oxides and hydroxides.

Answer 41

crystal form of pyrolusite

Question 42

What is the cleavage of pyrolusite?

Answer 42

Prismatic {110} perfect; fracture splintery.

Question 43

What is the hardness of pyrolusite?

Answer 43

1– 2 (often soils the fingers)

Question 44

What is the hardness for coarsely crystalline polianite?

Answer 44

6 –6 1/2

Question 45

What is the specific gravity of pyrolusite?

Answer 45

4.75

Question 46

What is the usual color of pyrolusite?

Answer 46

Iron black. Streak also iron black.

Question 47

It is the most common manganese ore mineral and is widespread in its occurrence. It is found as nodular deposits in bogs, on lake bottoms, and on the floors of oceans.

Answer 47

pyrolusite

Question 48

SnO2

Answer 48

Cassiterite

Question 49

When in crystals may show two tetragonal prisms and dipyramids. Often in elbow -shaped twins.

Answer 49

crystal form of cassiterite

Question 50

What is the cleavage of cassiterite?

Answer 50

Prismatic {010} imperfect

Question 51

What is the hardness of cassiterite?

Answer 51

6-7

Question 52

What is the specific gravity of cassiterite?

Answer 52

6.8-7.1

Question 53

What is the usual color of cassiterite?

Answer 53

Usually brown or black; rarely yellow or white. Streak white.

Question 54

Present as an accessory mineral of igneous rocks and pegmatites, but most commonly found in high-temperature hydrothermal veins in or near granitic rocks. Vein associations may include tourmaline, topaz, fluorite, apatite, molybdenite, and arsenopyrite

Answer 54

occurrence of cassiterite

Question 55

Cassiterite may also occur as rolled pebbles in placer deposits, know as __________.

Answer 55

stream tin

Question 56

Cassiterite may also have reniform shapes with radiating fibrous appearance, known as

Answer 56

wood tin

Question 57

UO2

Answer 57

Uraninite

Question 58

Most commonly as massive or botryoidal forms with a banded structure, known as ______.

Answer 58

crystal form of uraninite; pitchblende

Question 59

What is the hardness of uraninite?

Answer 59

5 1/2

Question 60

What is the specific gravity of uraninite?

Answer 60

6.5 – 9, for pitchblende. Crystals show G 7.5 – 9.7.

Question 61

What is the color of uraninite?

Answer 61

Black. Streak brownish black.

Question 62

A primary constituent of granitic rocks and pegmatites, and in high-temperature hydrothermal veins associated with cassiterite, chalcopyrite, and arsenopyrite.

Answer 62

uraninite