native elements Flashcards
gold crystal form
- isometric, octahedral crystals
- arborescent
- irregular, filliform, reticulated, dendritic
- irregular plates scales or masses
- rounded or flattened grains “nuggets”
gold cleavage
none. hackly fracture
gold hardness
2.5 to 3. malleable sectile
gold specific gravity
19.3 pure
15 impure with other metals
gold color
shades of yellow, paler with silver, metallic opaque
gold occurrence
- hydrothermal quartz veins (vv fine grained)
- placer deposits, conglomerates, detrital grains “nuggets”
gold remarks
- color, malleability and sectility
gold vs pyrite
gold vs chalcopyrite
pyrite is harder
chalcopyrite is brittle
silver crystal form
- isometric, malformed
- branching aborescent, reticulated groups
- in coarse or fine wire
- irregular masses, plates and scales
silver cleavage
none. hackly fracture
silver hardness
2.5 to 3. malleable and ductile
silver specific gravity
10.5 pure
10-12 impure
silver color
metallic opaque. silver white, tarnished brown to gray black
streak silver white
silver occurrence
large deposits from hydrothermal solution precipitates
in smaller amounts oxidized portions of ore deposits
silver remarks
- color, malleability and specific gravity
copper crystal form
- isometric, tetrahexahedral, cube, dodecahedral, octahedral, malformed branching and aborescent
- irregular masses plates and scales
- twisted and wirelike
copper cleavage
none. hackly fracture
copper hardness
2.5 to 3. ductile and malleable
copper specific gravity
8.9
copper color
dull luster, copper red, tarnish to dark
copper occurrence
- primary deposits associated with basaltic lavas, the copper is deposited through reaction of hydrothermal fluids with iron oxide minerals
- smaller amounts in oxidized zones of copper deposits associated with malachite azurite and cuprite
copper remarks
- copper red, malleability, high specific gravity hackly
sulfur crystal form
- orthorhombic, pyramidal, 2 dipyramids
- prism 011 and base
- masses perfectly crystallized
- massive reniform stalactitic incrustations
sulfur cleavage
none. conchoidal fracture to uneven. brittle
sulfur hardness
1.5 to 2.5
sulfur specific gravity
2.05 to 2.09
sulfur color
resinous. transparent to translucent. sulfur yellow. impure shades of green gray red
sulfur occurrence
- crater rims of extinct volcanoes as gas deposits
- veins with metallic sulfides from oxidation of sulfides
- in tertiary sedimentary rocks assoc. with anhydrite gypsum and limestone
- assoc with celestite, gypsum calcite and aragonite
sulfur remarks
- poor heat conductor
- cracks bc hear from hand expands the outside layers
- yellow color
diamond crystal form
- isometric, octahedral, cubes and dodecahedrons
- octahedral often has curved faces
- twins on 111
variety of diamond that has a rounded form and rough exterior resulting from radial or cryptocrystalline aggregate
bort
applies to badly colored or flawed diamonds without gem value
bort
diamond cleavage
octahedral 111 perfect
diamond hardness
10
diamond specific gravity
3.51
diamond color
adamantine. uncut greasy. colorless pale yellow. shades of red orange green blue brown.
deeper shades are rare
noncleavable, opaque, less brittle than crystals???
a black or grayish black bort
carbonado / carbon
diamond occurrence
- primary: in kimberlites as intrusive bodies, commonly circular with pipelike shape aka diamond pipes
- also in alluvial deposits (placers), bc of their inert nature, great hardness and high specific gravity
diamond remarks
- great hardness, adamantine, cleavage
graphite crystal form
- tabular crystals with hexagonal outline
- prominent basal face
- foliated or scaly masses
- radiated or granular
graphite cleavage
basal perfect 0001. flexible folia, not elastic
graphite hardness
1-2
graphite specific gravity
2.23
graphite color
metallic sometimes greasy. black black streak
graphite occurrence
- in metamorphic rocks: crystalline limestone, schists and gneiss
- hydrothermal veins associated with quartz, orthoclase, tourmaline, apatite, pyrite and titanite
- also original constituent in some igneous rocks
graphite remarks
- black, foliated, extreme softness, greasy
molybdenite vs graphite
moly has blue tone graphite is black