Where is Moonstone found?
Adularia (variety of Orthoclase 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
Historically the primary source of high-quality blue moonstone, particularly from the Meetiyagoda mines.
India
Produces a significant amount of moonstone, often with a more milky or brownish body color and a less intense blue flash.
Myanmar (Burma)
Known for producing fine moonstone, sometimes with a strong blue adularescence.
Madagascar
A source of various feldspar varieties, including moonstone.
Tanzania
Produces moonstone, often with a yellowish or brownish tint.
Brazil
Some occurrences of moonstone have been reported.
United States (e.g., New Mexico, Virginia)
Minor occurrences of moonstone have been found in various states.
Collecting tips
- Look for Adularescence. The most crucial identifying feature is the adularescence. Rotate the specimen under a light source to observe the characteristic floating, bluish-white sheen. This effect is best seen in diffused light rather than direct, harsh light.
- Check for Cleavage. Feldspars, including moonstone, exhibit perfect cleavage in two directions at nearly right angles. This can be observed on broken surfaces.
- Hardness Test (with caution). Moonstone has a Mohs hardness of 6-6.5. It can scratch glass (hardness 5.5) but can be scratched by quartz (hardness 7). Use this test carefully on an inconspicuous area to avoid damaging a valuable specimen.
- Examine for Inclusions. Moonstone can sometimes contain fine needle-like inclusions (often rutile) or centipede-like inclusions, which can enhance or interfere with the adularescence.
- Distinguish from Imitations. Be aware of glass imitations or synthetic spinels that might mimic moonstone's appearance. These typically lack the natural adularescence and often show gas bubbles or swirl marks.
Quick Check
- Color:
- Colorless to white, gray, brown, yellow, pink, green, with a characteristic blue or white adularescence.
- Luster:
- Vitreous to pearly.
- Streak:
- White.
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