Black Moonstone
The Dark Moon Crystal
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Quick Facts
Formation & Origin
Black moonstone is a dark-bodied variety of feldspar that shows silvery or blue schiller (adularescence or labradorescence) when light catches the internal structure at the right angle. The dark background intensifies the optical effect, creating a dramatic flash against a near-black base.
The exact mineralogy of 'black moonstone' varies by source. Some material is genuinely dark orthoclase (true moonstone, potassium feldspar) with adularescence. Other material sold as black moonstone is actually dark labradorite (plagioclase feldspar) with labradorescence. Both display attractive light effects, but through slightly different optical mechanisms.
The dark body color comes from microscopic inclusions of iron oxide, magnetite, or other dark minerals dispersed throughout the feldspar. These inclusions reduce transparency while providing a contrasting backdrop that makes the silvery-blue flash more visible.
Identification Guide
Black moonstone is identified by its dark gray to black feldspar body with silvery or blue schiller visible when rotated in light. Hardness 6, two cleavage directions, and characteristic optical flash confirm feldspar identity.
Distinguish from obsidian (glassy, no cleavage, no schiller), black labradorite (may be the same material under a different name), and larvikite (similar but is a rock containing multiple minerals, not a single crystal).
Spotting Fakes
The main issue isn't faking but naming confusion. 'Black moonstone' and 'black labradorite' are often the same material. Some sellers also label dark larvikite (a Norwegian rock) as black moonstone. For buyers, the practical question is: does the stone show an attractive flash? If it does, the mineralogical distinction is mostly academic. Black dyed glass without internal flash would be a true fake.
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Cultural & Metaphysical Traditions
Presented as cultural traditions, not scientific evidence
Black moonstone is associated with the new moon, shadow work, and the integration of unconscious patterns. Where white moonstone represents the full moon's illumination, black moonstone represents the introspective darkness of the new moon. Practitioners use it for deep meditation, psychic protection, and working through hidden emotional patterns.
Metaphysical and “healing” associations are cultural traditions, not medical advice or scientific fact. Crystals are not a substitute for professional medical care.
Where It's Found
Primary commercial source
Some material available
Occasional specimens
Price Guide
Good to Know
Scratch test: At hardness 6, Black Moonstone resists scratching from a knife but can be scratched by quartz. Best for pendants and earrings rather than rings.
Global supply: Found in 3 notable locations worldwide, from Madagascar to Sri Lanka.
Heft test: Black Moonstone has average mineral density (2.55-2.63). It feels about as heavy as you'd expect from a stone its size.
Care & Safety
What black moonstone can and cannot tolerate, based on its hardness (Mohs 6) and chemistry (KAlSi₃O₈ (potassium feldspar with labradorite)).
Can Black Moonstone go in water?
Yes. Black Moonstone is not water-soluble and durable enough (Mohs 6), so plain water is fine for rinsing and cleaning with mild soap. Avoid prolonged soaking, which serves no purpose, and dry the stone afterward.
Can Black Moonstone go in salt water?
Not recommended, even though black moonstone itself is hard and not water-soluble. Salt is corrosive and mildly abrasive: it can dull a polished surface, attack metal settings, and crystallize inside small fractures as the stone dries. A brief dip will not destroy black moonstone, but rinse it with fresh water afterward and dry it. For routine cleaning, plain water is the safer choice.
Sources & References
The mineralogical and gemological data on this page is drawn from and can be cross-checked against these external references.
- WikipediaMoonstone (gemstone) on Wikipedia
- WebmineralOrthoclase mineral data (Webmineral)
- Handbook of MineralogyOrthoclase (Handbook of Mineralogy, PDF)
- GIABlack Moonstone in the GIA Gem Encyclopedia
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