hydroxides

Question 1

how to distinguish oxides from hydroxides

Answer 1

the presence of OH- or H2O molecules

Question 2

what is the effect of OH- in the bonds

Answer 2

weakens them

Question 3

brucite formula

Answer 3

Mg (OH)2

Question 4

brucite form

Answer 4

• hexagonal, tabular
• more commonly foliated massive

Question 5

brucite cleavage

Answer 5

basal perfect. sectile, flexible folia not elastic

Question 6

brucite hardness

Answer 6

2.5

Question 7

brucite specific gravity

Answer 7

2.39

Question 8

brucite color

Answer 8

• pearly on base, waxy and vitreous elsewhere
• white gray light green

Question 9

brucite occurrence

Answer 9

• in assoc with serpentine dolomites, magnetite and chromite
• reaction product of Mg silicates, esp serpentine

Question 10

brucite remarks

Answer 10

foliated nature, light color, pearly on cleavage

Question 11

how to tell brucite from talc

Answer 11

brucite is harder (2.5) talc is 1

Question 12

how to distinguish brucite from mica?

Answer 12

brucite is inelastic

Question 13

manganite formula

Answer 13

MnO (OH)

Question 14

manganite form

Answer 14

• monoclinic, prismatic parallel to c, vertically striated
• often columnar to coarse, fibrous
• contact and penetration twins common

Question 15

manganite cleavage

Answer 15

perfect pinacoidal

Question 16

manganite hardness

Answer 16

4

Question 17

magnanite specific gravity

Answer 17

4.3

Question 18

manganite color

Answer 18

• metallic, opaque
• steel gray to iron black. streak is dark brown

Question 19

manganite occurrence

Answer 19

• in manganese deposits assoc eith other mn oxides and hydroxides
• in low temp veins assoc with barite, siderite and calcite

Question 20

manganite occurrence

Answer 20

• manganese deposits assoc with other Mn-oxides and hydroxides
• in low-temperature hydrothermal veins associated with barite, siderite, and calcite

Question 21

what does manganite commonly alter into

Answer 21

pyrolusite

Question 22

manganite remarks

Answer 22

black color, prismatic, 4 hardness

Question 23

how to distinguish manganite from pyrolusite

Answer 23

pyrolusite has iron black streak, manganite has dark brown streak

Question 24

romanechite formula

Answer 24

basta Ba, H2O, mn 4+ 3+ and O10

Question 25

romanechite form

Answer 25

amorphous, massive botryoidal, stalactitic

Question 26

romanechite hardness

Answer 26

5-6

Question 27

romanechite specific gravity

Answer 27

3.7 to 4.7

Question 28

romanechite color

Answer 28

submetallic opaque. black brownish black streak

Question 29

romanechite occurrence

Answer 29

- from secondary alteration of original Mn-carbonates, Mn-silicates, or both - in assoc with pyrolusite in manganese ore deposits - in nodular deposits in bogs, and on lake bottoms and on see and ocean floors

Question 30

former term for the hard botryoidal masses of which are mixtures of manganese oxides of which romanechite is a major constituent

Answer 30

psilomelane

Question 31

how to distinguish romanechite from other manganese oxides?

Answer 31

its hardness and botryoidal form

Question 32

how to distinguish romanechite from limonite

Answer 32

romanechite has a brownish black streak

Question 33

geothite formula

Answer 33

FeO (OH)

Question 34

geothite form

Answer 34

- rarely orthorhombic prismatic, vertically striated - massive, reniform, stalactitic in radiating fibrous aggregation - foliated

Question 35

loose and porous geothite

Answer 35

bog ore

Question 36

geothite cleavage

Answer 36

pinacoidal perfect

Question 37

geothite hardness

Answer 37

5 to 5.5

Question 38

geothite specific gravity

Answer 38

4.37, if impure as low as 3.3

Question 39

geothite color

Answer 39

- adamantine to dull, silky, scaly fibrous - yellowish brown to dark brown - yellowish brown streak. subtranslucent

Question 40

geothite occurrence

Answer 40

- common resulting from oxidation and weathering of iron bearing minerals - widespread in bogs and around springs

Question 41

where is geothite in metalliferous vein deposits?

Answer 41

the iron hat, the gossan

Question 42

how to distinguish geothite from colloform hematite and romanechite

Answer 42

hematite is black to brownish red geothite is yellowish brown to black and romanechite is just black

Question 43

limonite formula

Answer 43

FeO (OH) nH2O

Question 44

field term used for very fine grained to amorphous mictures of brown ferric hydroxides with unknown real identities

Answer 44

limonite

Question 45

commonly, what is the biggest composition of limonite

Answer 45

geothite

Question 46

T or F bauxite is a mineral/mineral species

Answer 46

F, it is a rock term

Question 47

bauxite consists of very fine grained intergrowth of three aluminum oxides, what are they

Answer 47

diaspore, gibbsite and boehmite

Question 48

bauxite is what type of ore

Answer 48

major aluminum ore

Question 49

bauxite form

Answer 49

- micture, pisolitic round concretionary grains - also massive, earthy claylike

Question 50

bauxite hardness

Answer 50

1-3

Question 51

bauxite specific gravity

Answer 51

2 to 2.55

Question 52

bauxite color

Answer 52

dull earthy - white gray red yellow

Question 53

what causes yellow color of bauxite

Answer 53

limonite staining

Question 54

bauxite occurrence

Answer 54

- eupergene, in subtropical or tropical conditions, prolonged weathering and leaching of silica from aluminum bearing rocks

Question 55

soil consisting mainly of hydrous aluminum and ferric oxides

Answer 55

laterite

Question 56

bauxite remarks

Answer 56

light, yellowish brown color, pisolitic, earthy tecture and low degree of hardness