Where is Moonstone found?
Orthoclase Feldspar (Adularia variety)
Got a photo? Identify rocks instantly with the Rockby app
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
Historically the most significant source, particularly for fine blue moonstone. Found in pegmatites and alluvial deposits.
India
Known for producing 'rainbow moonstone' (a variety of labradorite with a strong play-of-color, often misidentified as true moonstone) and some white and peach moonstone.
Myanmar (Burma)
Produces high-quality moonstone, often with a strong blue adularescence.
Madagascar
A source of various feldspar minerals, including some moonstone varieties.
Tanzania
Known for some moonstone occurrences.
United States (e.g., New Mexico, Virginia, Pennsylvania)
Minor occurrences of moonstone have been reported in various states, often in pegmatites or hydrothermal veins.
Brazil
Some deposits of moonstone have been found.
Collecting tips
- Look for Feldspar-Rich Environments. Moonstone is a feldspar, so search in areas known for pegmatites, granites, syenites, or hydrothermal veins. These are common environments for feldspar crystallization.
- Identify Adularescence. The key identifying feature is the adularescence. Rotate potential specimens under a light source to observe the characteristic shimmering, milky, or bluish sheen that appears to float within the stone. This effect is best seen on smooth, rounded surfaces.
- Check for Cleavage. Feldspars exhibit good cleavage in two directions. Look for flat, reflective surfaces where the mineral has broken along these planes. The angles between these cleavage planes can help distinguish between orthoclase (near 90°) and plagioclase (slightly less than 90°).
- Consider Hardness. Moonstone has a Mohs hardness of 6-6.5. While not a definitive field test, it can help rule out much softer or harder minerals. It can be scratched by quartz but will scratch glass.
- Examine Crystal Habit. While often massive, moonstone can form prismatic or tabular crystals. Look for these forms in vugs or pockets within host rocks.
Quick Check
- Color:
- Colorless to white, gray, peach, yellow, blue, with adularescence.
- Luster:
- Vitreous to pearly.
- Streak:
- White.
Explore Moonstone
Identify rocks anywhere
Free on iOS, Android, and Web. Photo identification, full database, and your personal collection.