native elements Flashcards
(47 cards)
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