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Friday, August 3, 2012

Using the Mineral Identification Chart for Identifying Gold in the Field

Gold Nugget
Photo by Rob Lavinsky


Sample No.
100
101
102
103
Color
Gold
Brass-Yellow
Pale Brass/Yellow
Brownish/Gold weathered
Luster
Metallic
Metallic
Metallic
Glassy
Crystal System
Isometric
Tetragonal
Isometric
Monoclinic
Composition
Au +Ag
FeCuS2
FeS2
X2Y4–6Z8O20(OH,F)4
Form
Nugget
Crystalline
Crystalline
Crystalline
Hardness
2.76
3.75 Avg.
6.25 Avg.
2.25
Streak
Gold
Greenish-Black
Greenish-Black
White
Sp. Gravity
17.8 Avg.
4.18 Avg.
4.9 Avg.
2.8
Cleavage
No
Poor/Indistinct
Poor/Indistinct
Perfect
Fracture
Hackly
Uneven
Concoidal
Micaeous
Florescent
No
No
No
No
Phosphorescent
No
No
No
No
Sectile
Yes
No
No
No
Malleable
Yes
No
No
No
Brittle
No
Yes
Yes
Elastic
Ferro-Magnetic
No
No
No
No
Para-Magnetic.
No
Yes
Yes
No
Non-Magnetic
Yes
No
No
Yes
Transparent
No
No
No
Yes
Translucent
No
No
No
No
Opaque
Yes
Yes
Yes
No
Mineral
Gold
Chalcopyrite
Iron Pyrite
Weathered Mica

As you can see from the chart gold has entirely different characteristics then “fools gold.”

According to Mindat.org gold has a specific gravity ranging from 16 to 19 depending on how pure it is.

Hardness is 2.5 to 3.

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