How to identify Veined Sandstone

To correctly identify Veined Sandstone (Sandstone with Quartz Veins), 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

   Sandstone matrix color varies widely (white, gray, tan, brown, red, yellow) depending on its composition and cementing agents. Quartz veins are typically white, milky, or translucent, sometimes clear.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Sandstone matrix typically dull to earthy. Quartz veins exhibit a vitreous (glassy) luster.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Sandstone matrix is clastic, granular, and often gritty to the touch, with visible sand grains. Quartz veins are crystalline, often massive, and can be smooth or show crystal faces if the fracture was large enough for euhedral growth.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Sandstone grains are typically sub-angular to rounded detrital grains. Quartz in veins forms anhedral to subhedral crystals filling fractures, sometimes euhedral if space allowed.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Sandstone matrix generally lacks cleavage, though some minerals within it might. Quartz veins exhibit no true cleavage but show conchoidal fracture.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Common in areas that have experienced tectonic deformation (faulting, folding) or hydrothermal activity, often associated with mountain building, basin inversion, or magmatic intrusions. Can be found in sedimentary basins that have undergone deep burial and diagenesis.

Key Facts

Hardness

Sandstone matrix: 2-7 (depending on cement and grain composition); Quartz veins: 7 (Mohs scale)

Specific Gravity

Sandstone matrix: 2.2-2.8 g/cm³; Quartz veins: 2.65 g/cm³

Crystal System

Sandstone grains: Variable (often anhedral); Quartz veins: Trigonal (for quartz)

Color

Sandstone: Highly variable (white, gray, tan, red, brown, yellow); Quartz veins: White, milky, translucent, clear.

Luster

Sandstone: Dull, earthy, sometimes vitreous; Quartz veins: Vitreous.

Transparency

Sandstone: Opaque to translucent; Quartz veins: Translucent to transparent.

Fracture

Sandstone: Granular, irregular; Quartz veins: Conchoidal.

Cleavage

Sandstone: None (though individual grains may have cleavage); Quartz veins: None.

Composition

Sandstone: Predominantly SiO2 (quartz), with varying amounts of feldspar, lithic fragments, and cementing minerals (silica, calcite, iron oxides, clay). Quartz veins: Nearly pure SiO2.

Physical characteristics

• Crystal Habit: Sandstone: Detrital, clastic grains; Quartz veins: Massive, anhedral to subhedral crystalline aggregates, sometimes euhedral crystals in open spaces.
• Cleavage Type: None for the rock as a whole; individual mineral grains may exhibit cleavage (e.g., feldspar). Quartz veins have no cleavage.
• Fracture Type: Sandstone: Granular, irregular; Quartz veins: Conchoidal.
• Tenacity: Brittle
• Luster Type: Sandstone: Dull to earthy; Quartz veins: Vitreous.

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