How to identify Gold-bearing Quartz Vein

To correctly identify Gold-bearing Quartz Vein (Quartz with native gold (Au)), check each of these features in order. Many rocks and minerals look alike, so cross-reference multiple properties before deciding.

Step-by-step identification

1. 1

   Color

   Overall color and any zoning or banding

   Quartz is typically white, milky, gray, or translucent. Native gold appears bright metallic yellow to brassy yellow. Oxidation of associated sulfides can impart reddish-brown or rusty stains.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Quartz has a vitreous (glassy) luster. Native gold has a distinctive metallic luster.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Quartz can be massive, granular, or crystalline. Gold typically occurs as disseminated flakes, wires, nuggets, or dendritic growths within the quartz, or along fracture surfaces.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Quartz often forms euhedral to anhedral crystals, sometimes as prismatic crystals with pyramidal terminations. Native gold typically occurs as anhedral masses, flakes, wires, or rarely as small octahedral or dodecahedral crystals.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Quartz exhibits no true cleavage, but rather conchoidal fracture. Native gold has no cleavage, but is highly malleable.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Found in various geological settings, including mesothermal and epithermal vein systems associated with orogenic belts, porphyry copper-gold deposits, and volcanic-hosted massive sulfide (VHMS) deposits. Often hosted in shear zones, faults, and fractures within igneous, metamorphic, or sedimentary rocks.

Key Facts

Hardness

Quartz: 7 on Mohs scale. Gold: 2.5-3 on Mohs scale.

Specific Gravity

Quartz: 2.65 g/cm³. Gold: 19.3 g/cm³ (pure gold), but can vary in alloys.

Crystal System

Quartz: Trigonal. Gold: Isometric.

Color

Quartz: Colorless, white, milky, gray. Gold: Golden yellow.

Luster

Quartz: Vitreous. Gold: Metallic.

Transparency

Quartz: Transparent to opaque. Gold: Opaque.

Fracture

Quartz: Conchoidal. Gold: Hackly.

Cleavage

Quartz: None. Gold: None.

Composition

Quartz: Silicon dioxide (SiO2). Gold: Native element (Au), often alloyed with silver (electrum) or other metals.

Physical characteristics

• Crystal Habit: Quartz: Prismatic, massive, granular. Gold: Dendritic, arborescent, wire-like, flaky, massive, rarely euhedral crystals.
• Cleavage Type: Quartz: None. Gold: None.
• Fracture Type: Quartz: Conchoidal. Gold: Hackly.
• Tenacity: Quartz: Brittle. Gold: Malleable and ductile.
• Luster Type: Quartz: Vitreous. Gold: Metallic.

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