How to identify Mixed Tumbled Stones

To correctly identify Mixed Tumbled Stones (Serpentine, Quartz, Jasper), 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

   Serpentine: Various shades of green (light to dark), yellowish-green, brownish-green, sometimes black. Quartz: Colorless, white, milky, pink (rose quartz), purple (amethyst), yellow (citrine), brown (smoky quartz), black (morion). Jasper: Opaque, typically red, yellow, brown, green, blue, often multi-colored with patterns. The tumbled nature means colors are enhanced and often more vivid.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Serpentine: Greasy, waxy, silky (fibrous varieties). Quartz: Vitreous (glassy). Jasper: Dull to sub-vitreous.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Smooth and polished due to tumbling. Serpentine may feel slightly soapy. Quartz will feel hard and smooth. Jasper will feel smooth and dense.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Tumbled stones do not retain their original crystal forms. Serpentine typically occurs in massive, fibrous, or platy aggregates. Quartz forms hexagonal prisms with pyramidal terminations. Jasper is cryptocrystalline, meaning its crystals are microscopic.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Serpentine: Poor to distinct in some varieties (e.g., antigorite), often masked by massive habit. Quartz: None (conchoidal fracture). Jasper: None (conchoidal to splintery fracture).

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Serpentine: Serpentinite bodies, often associated with ophiolites and subduction zones. Quartz: Ubiquitous in igneous, metamorphic, and sedimentary rocks. Jasper: Hydrothermal veins, volcanic deposits, sedimentary beds, often associated with chert or iron formations.

Key Facts

Hardness

Serpentine: 2.5-5 (Mohs). Quartz: 7 (Mohs). Jasper: 6.5-7 (Mohs).

Specific Gravity

Serpentine: 2.5-2.6. Quartz: 2.65. Jasper: 2.58-2.91.

Crystal System

Serpentine: Monoclinic (chrysotile, antigorite, lizardite). Quartz: Trigonal. Jasper: Trigonal (cryptocrystalline).

Color

Serpentine: Green, yellowish-green, brownish-green, black. Quartz: Colorless, white, milky, pink, purple, yellow, brown, black. Jasper: Red, yellow, brown, green, blue, multi-colored.

Luster

Serpentine: Greasy, waxy, silky. Quartz: Vitreous. Jasper: Dull to sub-vitreous.

Transparency

Serpentine: Translucent to opaque. Quartz: Transparent to translucent. Jasper: Opaque.

Fracture

Serpentine: Splintery, conchoidal, uneven. Quartz: Conchoidal. Jasper: Conchoidal to splintery.

Cleavage

Serpentine: Poor to distinct in some varieties, often not observed. Quartz: None. Jasper: None.

Composition

Serpentine: Hydrous magnesium iron phyllosilicate ((Mg,Fe)3Si2O5(OH)4). Quartz: Silicon dioxide (SiO2). Jasper: Cryptocrystalline silicon dioxide (SiO2) with various mineral inclusions (e.g., iron oxides) causing color.

Physical characteristics

• Crystal Habit: Tumbled stones obscure original habit. Serpentine: Massive, fibrous, platy. Quartz: Prismatic, massive, granular. Jasper: Massive, nodular, botryoidal.
• Cleavage Type: Serpentine: Variable, often poor. Quartz: None. Jasper: None.
• Fracture Type: Serpentine: Splintery, conchoidal, uneven. Quartz: Conchoidal. Jasper: Conchoidal to splintery.
• Tenacity: Serpentine: Brittle to tough. Quartz: Brittle. Jasper: Tough.
• Luster Type: Serpentine: Greasy, waxy, silky. Quartz: Vitreous. Jasper: Dull to sub-vitreous.

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