Where is Moonstone found?
Adularia (Orthoclase variety) or Oligoclase (Plagioclase Feldspar)
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Open the appMoonstone occurs in specific geological environments. Knowing where to look, and in what kind of rock, is the difference between going home empty-handed and finding a great specimen.
Where to find Moonstone
Sri Lanka
Known for producing high-quality blue moonstone, often found in alluvial deposits.
India
Source of 'rainbow moonstone' (a variety of labradorite with a strong blue schiller) and other colors.
Myanmar (Burma)
Historically a significant source of fine moonstone.
Madagascar
Produces various colors of moonstone, including peach and white.
Tanzania
Known for some moonstone occurrences.
Brazil
Some deposits of moonstone have been found.
United States (e.g., New Mexico, Virginia, Pennsylvania)
Minor occurrences of moonstone have been reported in pegmatites and other igneous rocks.
Collecting tips
- Look for Feldspar-Rich Environments. Moonstone is a feldspar, so target areas known for pegmatites, granites, and other feldspar-rich igneous or metamorphic rocks.
- Examine Alluvial Deposits. Many gem-quality moonstones are found in secondary alluvial deposits, so search riverbeds and gravels in known moonstone-producing regions.
- Observe for Adularescence. The most distinctive feature is the adularescence. Rotate potential specimens under a light source to check for the characteristic internal glow or shimmer.
- Check for Cleavage. Feldspars have distinct cleavage planes. Look for two cleavage directions at or near 90 degrees.
- Consider Hardness. Moonstone has a Mohs hardness of 6-6.5, meaning it can be scratched by quartz but will scratch glass. This can help differentiate it from softer minerals.
Quick Check
- Color:
- Colorless, white, gray, peach, blue (often with adularescence)
- Luster:
- Vitreous to pearly
- Streak:
- White
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