mineral

Quartz Mix and Feldspar Group

Silicon Dioxide (SiO2) and Potassium Alumino-silicates (KAlSi3O8)

Hardness: 6-7 (Mohs scale); Colors: white, cream, tan, and grey; Luster: Vitreous to pearly; Crystal structure: Trigonal or Monoclinic; Cleavage: None (Quartz) to perfect (Feldspar); Specific gravity: 2.5-2.7

Hardness: 6-7 (Mohs scale)
Luster: Vitreous to pearly

Identified July 9, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the cooling of igneous magmas or precipitation from hydrothermal veins. These are fundamental building blocks of the Earth's crust, found in virtually all geological environments from ancient mountain ranges to modern river beds.

Uses & applications

Quartz is used in glass making, electronics, and construction; Feldspar is used in ceramics, porcelain, and as fillers in paint and rubber. Both are popular for hobbyist collecting.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Feldspar is actually the single most abundant group of minerals, making up about 60% of the Earth's crust.

Field identification & locations

Identify Quartz by its lack of cleavage and 'glassy' fracture; identify Feldspar by its flatter, reflective cleavage planes. Commonly found in gardens, gravel pits, and mountain trails. Collectors should look for distinct crystal faces or unique staining.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Gypsum (variety Selenite or Alabaster)

Calcium sulfate dihydrate (CaSO4·2H2O)

Mineral

Nephrite Jade

Nephrite

Mineral/Rock

Granite

Granite (Phaneritic intrusive igneous rock)

igneous