What is Microcline?
Microcline is the low-temperature potassium feldspar, known for perthitic textures, grid twinning and amazonite varieties.
Mineralogy and structure
The reference formula is KAlSi3O8. Microcline is classified with the silicates and its crystal system is triclinic. Natural specimens can vary in composition, habit and degree of crystallinity, so the locality and observed form remain important.
Colour and appearance
Typical colours include white, cream, pink, green and blue-green. Lustre, transparency, inclusions and surface condition should be described for the individual specimen rather than inferred from the name alone.
Formation and localities
Microcline forms in or is associated with granites, pegmatites, gneisses and hydrothermal alteration zones. Notable collecting regions include Brazil, Madagascar, Russia, Norway, Austria and the United States. A precise locality is more useful than a broad country label when it is documented.
Collecting notes
Microcline is useful in a reference collection because its appearance connects mineral chemistry with geological setting. Store specimens dry, protected from impact and clearly labelled with the confirmed material, locality and any treatment history.
