How to identify Scheelite with Quartz and Pyrite

To correctly identify Scheelite with Quartz and Pyrite (CaWO4 (Scheelite), SiO2 (Quartz), FeS2 (Pyrite)), 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

   Scheelite: White, yellow, yellowish-brown, greenish-yellow, or colorless. Quartz: Colorless, white, or various hues depending on impurities. Pyrite: Pale brass-yellow, often tarnishing to iridescent colors.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Scheelite: Vitreous to adamantine. Quartz: Vitreous. Pyrite: Metallic.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Scheelite: Often granular, massive, or as distinct bipyramidal crystals. Quartz: Crystalline, massive, or granular. Pyrite: Crystalline (cubes, pyritohedrons, octahedrons), massive, or disseminated.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Scheelite: Tetragonal bipyramidal crystals, often pseudo-octahedral; also massive or granular. Quartz: Hexagonal prisms with pyramidal terminations; massive. Pyrite: Cubic, pyritohedral, or octahedral crystals; also massive or granular.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Scheelite: Distinct on {101} and {112}. Quartz: None (conchoidal fracture). Pyrite: Indistinct on {001} and {110}.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   High-temperature hydrothermal veins, skarns, greisen deposits, and contact metamorphic zones associated with granitic intrusions.

Key Facts

Hardness

Scheelite: 4.5-5 Mohs; Quartz: 7 Mohs; Pyrite: 6-6.5 Mohs

Specific Gravity

Scheelite: 5.9-6.1; Quartz: 2.65; Pyrite: 4.95-5.10

Crystal System

Scheelite: Tetragonal; Quartz: Trigonal; Pyrite: Isometric

Color

Scheelite: White, yellow, brownish; Quartz: Colorless, white; Pyrite: Brassy yellow

Luster

Scheelite: Vitreous to adamantine; Quartz: Vitreous; Pyrite: Metallic

Transparency

Scheelite: Transparent to translucent; Quartz: Transparent to translucent; Pyrite: Opaque

Fracture

Scheelite: Uneven to subconchoidal; Quartz: Conchoidal; Pyrite: Uneven to conchoidal

Cleavage

Scheelite: Distinct on {101} and {112}; Quartz: None; Pyrite: Indistinct on {001} and {110}

Composition

Scheelite: Calcium tungstate (CaWO4); Quartz: Silicon dioxide (SiO2); Pyrite: Iron disulfide (FeS2)

Physical characteristics

• Crystal Habit: Scheelite: Bipyramidal, massive, granular; Quartz: Prismatic, massive, granular; Pyrite: Cubic, pyritohedral, massive
• Cleavage Type: Scheelite: Distinct; Quartz: None; Pyrite: Indistinct
• Fracture Type: Scheelite: Uneven to subconchoidal; Quartz: Conchoidal; Pyrite: Uneven to conchoidal
• Tenacity: Scheelite: Brittle; Quartz: Brittle; Pyrite: Brittle
• Luster Type: Scheelite: Vitreous to adamantine; Quartz: Vitreous; Pyrite: Metallic

Explore Scheelite with Quartz and Pyrite