Meaning and Properties


Feldspar is a group of minerals containing potassium, sodium, calcium and aluminum silicates. Feldspar was given its name by Johan Gottschalk Wallerius in 1747. The name feldspar is derived from German "feld," meaning "field" because some early specimens were found in fields and "spar, " a geological term for non-metallic minerals with a vitreous luster and good cleavage.

Individual gemstones with the feldspar name now in the marketplace include:

  • Grey feldspar is a striking blend of grey and tan shades with black inclusions
  • Pink feldspar has distinct, marbled patterns of mauve, cream, grey and black tones
  • Graphic feldspar boasts a marbled appearance with varied black, grey and occasional brown translucent inclusions set in creamy tan stone
  • Brown feldspar has a marbled surface with tan and brown tones
  • Black spotted feldspar has a grey surface with black spots

Feldspar is an important and common raw material used to produce ceramics and geopolymers. Feldspar is also often used as an anti-caking agent in powdered forms of non-dairy creamer. Feldspar is an important ingredient in the manufacturing of glass. The alkali content in feldspar acts as a flux, lowering the glass batch melting temperature and reducing production costs.

Metaphysical Properties

Feldspar is believed by metaphysical adherents to be a gemstone of creativity. Feldspar helps with finding unconventional and exciting ways to achieve goals by stimulating creative thinking. Feldspar increases your self-respect, self-esteem and self-awareness.

Feldspar is believed to help to align our chakras, subtle bodies and meridians and is good for astral travel. Feldspar is associated with the astrological sign of Aquarius.

Geological Properties

Feldspar comprises almost 60% of the Earth's crust, making feldspar the most common mineral. Feldspar contains aluminum silicates with potassium, sodium, calcium and barium.

Feldspar group consists of mainly 3 mineral species:

  1. Microcline feldspar - a mineral species with chemical composition of KAlSi2O8. Amazonite is the variety under this mineral species.
  2. Orthoclase feldspar - mineral species with chemical composition of KAlSi3O8. Moonstone (white, gray, peach etc.) is the main variety under this mineral species.
  3. Plagioclase feldspar - mineral species with chemical composition NaAlSi3O8 and CaAl2Si2O8). Sunstone, labradorite and rainbow moonstone are main varieties under this mineral species.

Individual gemstones with the feldspar name, such as grey feldspar, come under the feldspar subgroup--or mineral species--microcline feldspar. Amazonite is another gemstone from the feldspar microcline subgroup. And, like Amazonite, gemstones with the feldspar name from the microcline species are found in Brazil, Colorado and Virginia in the United States, Australia and Madagascar.

Mineral Information Tektosilicate, microcline (feldspar group)
Chemical Composition KAlSi2O8
Color Colorless, yellow, green, blue-green, orange, red-brown, dark gray, gray-black.
Hardness 6 to 6-1/2 (Mohs)
Specific Gravity 2.56 - 2.75
Refractive Index 1.518 - 1.570

Proper Care of Feldspar

Feldspar gemstones of the microcline species are sensitive to chemicals, abrasives, heat, acids and ammonia. Never use a steamer, hot water or ultrasonic cleaners with these feldspar gemstones. Use mild soap and room temperature tap water with a soft cloth to retain the luster of the gemstone.

To learn more about Feldspar and other gemstones, order your copy of Walter Schumann's revised and expanded edition of Gemstones of the World.

Designing with Feldspar

The range of feldspar gemstone colors (or no color) offers a galaxy of design options. Grey feldspar with its neutral color can be used as a spacer, or it can be suited with sympathetic colors such as blue. The marbled patterns of mauve, cream, grey and black from pink feldspar work especially well with tan, black, or brown hues and well as deep greens. Graphic feldspar's marbled black, grey and brown set in creamy tan also work well with earth tones and shades of green.

View more resources featuring feldspar, including Design Ideas, Videos, Tutorials and more!

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