NATIVE ELEMENTS Flashcards
Au
Gold
Isometric, with crystals commonly octahedral. Often in arborescent crystal groups. Crystals may
be irregularly shaped, passing into filliform, reticulated, and dendritic shapes.
Gold
What is the hardness of gold?
2.5 - 3
What is the specific gravity of gold?
19.3
What is the usual color of gold?
Various shades of yellow depending on the purity, becoming paler with increasing silver content.
The chief sources are (1) hydrothermal – quartz veins in which it is commonly so fine-grained that its presence cannot be detected with the eye, and (2) placer deposits, and their lithified equivalents known as conglomerates, in which it occurs as fine detrital grains and nuggets.
Gold
Ag
Silver
Silver has a hardness of ________.
2.5 - 3
What is the specific gravity of Silver?
10.5 when pure, 10 - 12 when impure
Isometric crystals are commonly malformed and in branching, arborescent, or reticulated groups.
Silver
In large deposits has been precipitated from primary hydrothermal solutions. It is also distributed, in smaller amounts, in the oxidized zones of ore deposits.
Silver
Cu
Copper
Isometric crystals with tetrahexahedral, cube, dodecahedral, and octahedral faces are common.
Crystals are usually malformed and in branching and arborescent groups.
Copper
What is the hardness of copper?
2.5 - 3
What is the specific gravity of native copper?
8.9
What is the usual color of copper?
red on fresh surface, usually dark with dull luster because of tarnish.
Occur in the oxidized zones deposits associated with
cuprite, malachite, and azurite. Primary deposits are associated with basaltic lavas, where it was deposited through the reaction of hydrothermal solutions with iron oxide minerals.
Copper
Orthorhombic crystals with pyramidal habit, commonly with two dipyramids, prism {011}, and a base in combination.
Sulfur
T or F. Sulfur has a cleavage and fracture conchoidal to uneven.
F. only fracture conchoidal to uneven
What is the usual color of sulfur?
Yellow, varying with impurities to yellow shades of green, gray, and red.
Is found commonly at or near the crater rims of active or extinct volcanoes, deposited from
volcanic gases. It also occurs in veins with metallic sulfides formed by the oxidation of the
sulfides.
Sulfur
C
Diamond and graphite
Isometric crystals with octahedral form most common; cubes and dodecahedrons may occur as
well. Octahedral faces are frequently curved, and twins on {111} (spinel law) are common.
Diamond crystal form
_____ a variety of diamond, has rounded forms and a rough exterior resulting from a radial or cryptocrystalline aggregate. The term is also applied to badly colored or flawed diamonds without
gem value.
Bort
