Material
Feldspar with sheen
Classic moonstone contains orthoclase and albite. Other feldspars can also be recorded under the moonstone name.
Stone Explorer → Moonstone comparison tool
Moonstone records, side by side.
Compare 5 natural feldspar specimens, then follow how fine layers form inside classic moonstone.
Moonstone file · 5 natural specimen records
Two ways in · pick one
Each specimen opens its own file.
Evidence
What the image can show.
Use the images to compare stones. Check the record for identity and treatment.
Optics
Colour and sheen
Body colour and moving sheen describe separate features. Compare both as the light changes.
Records
The specimen entry
Catalogue entries retain locality and material labels. Treatment is unrecorded for these 5 specimens.
Sources
Sources + specimen credits
Material descriptions, naming and photograph records.
The nameMaterial and evidence
Classic moonstone is an orthoclase and albite intergrowth. Other feldspars can carry the moonstone name. “Rainbow moonstone” usually means labradorite.
GIA: Moonstone description · GIA: Is rainbow moonstone really moonstone?
Body colour and optical effectsMaterial and evidence
White and peach are body-colour labels; blue can describe the sheen. Cat’s-eye names a directional light band. These labels can overlap on one stone.
Durability and treatmentMaterial and evidence
Moonstone is about Mohs 6 to 6.5, with two cleavage directions. Treatment belongs to the individual record; filling and impregnation have been documented.
GIA: Moonstone care and cleaning · GIA: A spectroscopic study of filled moonstone
PhotographsMaterial and evidence
The images show natural reference specimens. Their catalogue labels, credits and licences are retained in each specimen file. Exact identity, treatment and origin require specimen-specific evidence.
Vassil: Orthoclase, moonstone · Rob Lavinsky: Plagioclase feldspar, moonstone, Pili Mine
Orthoclase moonstonePublic domain
Vassil, via Wikimedia Commons · Public domain
Original photograph. The card crops the frame; the specimen file shows the full image.
Plagioclase moonstoneCC BY-SA 3.0
Rob Lavinsky, iRocks.com, via Wikimedia Commons · CC BY-SA 3.0
Original photograph. The card crops the frame; the specimen file shows the full image.
Chihuahua moonstoneCC BY-SA 3.0
Rob Lavinsky, iRocks.com, via Wikimedia Commons · CC BY-SA 3.0
Original photograph. The card crops the frame; the specimen file shows the full image.
Formation drawingClassic alkali feldspar
The cutaway explains a possible exsolution pathway in classic moonstone. Enlarged layers and light are schematic. The drawing represents no particular deposit.
Body colour and moving sheenMaterial reference
Moonstone can be colourless, white, peach, grey to dark grey, green or yellow-brown. Adularescence is the blue, white or silvery light that appears to move below the surface as the viewing angle changes. Body colour and sheen are separate observations and can occur in different combinations.
Open sourceCat’s-eye and star effectsMaterial reference
Some moonstone shows a narrow cat’s-eye band; rare specimens show a four-rayed star. These effects depend on internal structure, lighting and the orientation of a curved polished surface. A broad patch of sheen or a bright cleavage reflection does not establish either effect. The rough photographs here are not cat’s-eye or star demonstrations.
Open sourceFeldspar identities and namesMaterial reference
Classic moonstone commonly contains intergrown alkali feldspars. Rainbow moonstone is a trade name often applied to labradorite, a plagioclase feldspar. Adularia names an orthoclase habit; it does not guarantee a visible moonstone sheen. A broad plagioclase catalogue label supplies neither a precise composition nor permission to rename that specimen rainbow moonstone.
Open source
