sulfates Flashcards
barite formula
BaSO4
barite crystal form
- orthorhombic, tabular on {001}
- frequently divergent groups or tabular crystals forming crested barite or barite roses
- coarsely laminated, granular, earthy
barite cleavage
pinacoidal perfect, prismatic less perfect
barite hardness
3 to 3.5
barite specific gravity
4.5
barite color
vitreous, transparent to translucent. pearly on the base on some. colorless white light shades of red blue and yellow
barite occurrence
hydrothermal veins associated with ores of silver, lead, copper, cobalt and manganese
barite remarks
yellowish green flame test
celestite formula
SrSO4
celestite crystal form
- orthorhombic tabular on {001}, same with barite
- prismatic parallel to the a or b axis
- radiating fibrous, granular
celestite cleavage
basal perfect, prismatic good
celestite hardness
3 to 3.5
celestite specific gravity
3.95 to 3.97
celestite color
vitreous to pearly transparent to translucent. colorless white and faintly red and blue
celestite occurrence
- disseminations in sandstone or limestone
- nests or lining of cavities in ss or ls
- lead veins with galena
celestite remarks
- usual pale blue color
- fine radiating/ fibrous habit
- crimson flame test and lower specific gravity
anglesite formula
PbSO4
anglesite crystal form
- orthorhombic, tabular on {001} like barite but more varied
- coarse, granular to compact
- earthy, concentric layers with unaltered galena core
anglesite cleavage
basal good, prismatic imperfect, conchoidal fracture
anglesite hardness
3
anglesite specific gravity
6.2 to 6.4
anglesite color
adamantine crystal, dull earthy. transparent to translucent. colorless white gray, pale shades of yellow. dark gray if impurities
anglesite occurrence
supergene mineral in oxidized portions of lead deposits
anglesite remarks
high specific gravity and adamantine luster, association with galena
anhydrite formula
CaSO4
anhydrite crystal form
- orthorhombic, crystals rare
- usually massive, crystalline massive resembling an isometric mineral with cubic cleavage
- fibrous, massive granular
anhydrite cleavage
3 pinacoidal
anhydrite hardness
3-3.5
anhydrite specific gravity
2.89 to 2.98
anhydrite color
vitreous to pearly on cleavage. colorless bluish to violet. white or tinged with rose red or brown
anhydrite occurrence
- same with gypsum, associated with gypsum but less common
- in beds associated with salt deposits in the caps of salt domes and in limestone
- in amygdaloidal cavities in basalt
anhydrite remarks
- 3 cleavages at right angles (diff from barite)
- higher specific gravity than calcite
- harder than gypsum
gypsum formula
CaSO4•2(H2O)
gypsum crystal form
- monoclinic, simple habit
- tabular on 010
- diamond shaped with beveled edges
- twinning on 100: swallowtail twins
gypsum cleavage
- 010 pinacoidal perfect
- 100 conchoidal
- 110 fibrous fracture
gypsum hardness
2
gypsum specific gravity
2.32
gypsum color
pearly, vitreous, silky. translucent to transparent. colorless white gray yellow red brown. satin spar alabaster and selenite
gypsum occurrence
- in sedimentary rocks as thick beds: interstratified with limestone and shale or underlying beds of rock salt, alteration of anhydrite
- volcanic regions
- gangue of metallic veins
gypsum remarks
softness, three unequal cleavages