As an Amazon Associate, I earn from qualifying purchases with no additional costs for you.
Moonstone is a variety of the feldspar minerals orthoclase and albite, prized for adularescence – the floating, moonlight-like sheen created by microscopic layers of the two minerals scattering light inside the stone.
Ordinary moonstone runs about $1.30–$15 per carat, while the rarer blue-sheen rainbow moonstone can reach $50–$60 per carat for top quality.
Virginia, North Carolina, and Georgia are the best-known U.S. sources; the quickest field check is tilting the stone under a light source and watching for that soft, billowing glow moving across the surface as you turn it.
What Is Moonstone, and How Does It Form?
Moonstone isn’t a single mineral – it’s a variety of the feldspar-group minerals orthoclase and albite, and its famous glow comes entirely from how those two minerals grow together, not from any exotic ingredient.
As magma cools deep underground, orthoclase and albite crystallize together as a single mineral at first. As the rock continues cooling slowly, the two feldspars “unmix” and separate into microscopically thin, alternating layers – a process geologists call exsolution.
Light entering the stone scatters off these stacked layers and reflects back out as a soft, billowing glow that seems to float just beneath the surface as the stone is tilted – an optical effect called adularescence. Despite the name, moonstone has nothing to do with the Moon; the name refers only to its moonlight-like appearance.
Moonstone is frequently confused with two other feldspar-family gems that share its floating-light look but form the effect differently. Labradorite shows a similar internal glow, called labradorescence, but the light plays across broad flashes of blue, green, and gold rather than moonstone’s soft, milky sheen, and labradorite is typically darker-bodied overall. “Rainbow moonstone” is itself a trade name for a colorless variety of labradorite showing a blue-to-multicolor sheen – gemologically it isn’t true moonstone at all, even though it’s sold and marketed as one.
- Mineral group: feldspar (orthoclase intergrown with albite)
- Hardness: 6–6.5 on the Mohs scale
- Signature optical effect: adularescence – a floating, bluish-white sheen caused by light scattering off layered feldspar
- Common body colors: colorless, white, gray, peach, and (rarer) gray-green
The name “moonstone” is a relatively modern, romantic label; mineralogists once called the same material adularia, after Switzerland’s Adula Mountains, where fine specimens were historically found in alpine cavities. The two names are still used somewhat interchangeably in older gemological texts, though “moonstone” has become the standard trade term worldwide.
Real vs. Fake Moonstone: How to Tell
Moonstone’s glow is easy to fake with glass, opalite, or plastic, all of which are sold as “moonstone” in jewelry markets – but each imitation gives itself away under a close look.
Two further checks help separate a real stone from convincing imitations. Moonstone’s refractive index (roughly 1.518–1.526) is noticeably lower than glass (around 1.5 but often inconsistent) or synthetic spinel used in some fakes (1.72), so a jeweler’s refractometer settles the question in seconds.
A loupe or hand lens also helps: real moonstone can show faint, needle-like internal inclusions from its layered structure, while cast-glass imitations are far more likely to be perfectly clean inside. A jeweler’s loupe magnifies these details enough for most buyers to check on the spot, without needing lab equipment.
And because natural moonstone is uniaxial with a layered internal structure, its adularescence typically appears strongest along one direction as the stone is rotated, while glass and plastic imitations often show an even, direction-independent glow instead.
| Feature | Real Moonstone | Fake (Glass, Opalite, or Plastic) |
|---|---|---|
| Adularescence color | A single, consistent sheen color across the whole stone – usually blue or white | Opalite often shows a shifting rainbow of sheen colors from yellow to blue on the same stone |
| Touch test | Feels cold to the touch for a few seconds before warming | Plastic warms almost immediately; glass and opalite stay cold slightly longer but not as long as real feldspar |
| Hardness | 6–6.5 on the Mohs scale – resists scratching from a fingernail or copper coin | Glass and opalite sit around 5; molded plastic is 3–4 and scratches easily |
| Internal fractures | Tiny natural fractures, often two sets crossing at a right angle | No natural fracture pattern – interior looks uniform and flawless |
| Air bubbles | None – natural feldspar has no trapped gas bubbles | Glass fakes frequently show tiny trapped air bubbles under magnification |
The single most reliable field test is the adularescence itself: real moonstone shows one steady sheen color as you tilt it, while a glass or opalite imitation often flashes through several different colors on the same stone – a giveaway that jewelers and gemologists check for first.
How Much Is Moonstone Worth?
Gem-quality moonstone is priced mainly on the strength and evenness of its adularescence, with the type of sheen driving most of the price difference between varieties.
| Type | Price Per Carat |
|---|---|
| Standard moonstone | $1.30 – $15 |
| Star moonstone | $2 – $30 |
| Cat’s eye moonstone | $3 – $50 |
| Rainbow (blue-sheen) moonstone | $5 – $60 |
A finished ring or small bracelet set with top-quality moonstone typically runs around $250. Loose calibrated stones in common sizes (6x8mm or 8x10mm ovals) are priced far more predictably than one-off custom cuts, since jewelers can buy and set them without paying a premium for bespoke lapidary work.
The most prized stones show a clear body with a vivid blue adularescence that seems to float right at the surface from every angle – the largest and most famous example of this quality was a 450-carat stone found near Mount Kilimanjaro, on the border of Tanzania and Kenya.
Cut also drives price more than with most gems: moonstone is almost always cabochon-cut with a domed top, because faceting flattens and scatters the very light-scattering layers that create adularescence in the first place.
A well-proportioned, symmetrical cabochon that centers the sheen directly under the dome commands a real premium over an off-center or lopsided cut of the same rough – cutting moonstone well is considered a specialized skill in the lapidary trade, distinct from the faceting skills used on transparent gems like sapphire or amethyst – cutting moonstone well is considered a specialized skill, and a poorly cut stone can waste rough that would otherwise have sold for far more.
Moonstone had a significant moment in jewelry history during the Art Nouveau period (roughly 1890–1910), when designers like René Lalique favored its soft, otherworldly glow for pendants, brooches, and hair ornaments over the harder sparkle of faceted diamonds and colored gemstones that dominated earlier Victorian jewelry. Original Art Nouveau pieces set with fine moonstone are now collector’s items in their own right, valued as much for their age and craftsmanship as for the stone itself.
BTW: Do you want to know more about rock and mineral identification? The books listed below are the best ones you can find on the internet (Amazon links):
- Smithsonian Handbooks: Rocks & Minerals
- Gemstone & Crystal Properties (Quick Study Home)
- Ultimate Explorer Field Guide: Rocks and Minerals (National Geographic Kids)
Where to Find Moonstone
The world’s richest commercial moonstone deposits are overseas – Myanmar’s Mogok Valley, Sri Lanka, and India’s Jharkhand and Tamil Nadu regions supply most of the moonstone sold in jewelry – but the U.S. has its own scattered, rockhound-friendly deposits that don’t need to compete with a mining industry.
In the Appalachians, Virginia, North Carolina, and Georgia offer the best odds; the Rocky Mountains have fewer confirmed spots, but Colorado and New Mexico both have documented finds.
Prospecting tip that applies across all these states: moonstone-bearing pegmatites also tend to host other feldspar-group minerals and quartz, so a promising gravel bar or road cut that turns up milky quartz, mica flakes, or other pegmatite minerals is worth searching more thoroughly rather than moving on immediately. California has more mistaken identifications than genuine moonstone, though real specimens have turned up in the Funeral Range of Inyo County.
Within the Appalachian belt, the area around Little Switzerland and Spruce Pine in western North Carolina is one of the more consistently productive stretches, thanks to the same feldspar-rich pegmatites that also supply the region’s mica and gem mining tourist operations.
As with most feldspar hunting, moonstone in the U.S. is typically found as float in stream gravels and residual soil rather than mined directly from bedrock, so working creek beds and old pegmatite spoil piles tends to be more productive than prospecting solid outcrops.
Overseas, Sri Lanka’s moonstone mines near Meetiyagoda, on the island’s southwest coast, are considered the world’s premier source of the finest blue-sheen material and have been worked for centuries; Myanmar’s Mogok Valley, better known for ruby and sapphire, also produces moonstone as a byproduct of the same alluvial gem gravels.
Most rough from these deposits is cut in Sri Lanka or India before reaching international jewelry markets, which is part of why a stone’s cutting origin is sometimes used as an (imperfect) proxy for quality when the mine of origin isn’t documented.
| State | Best Locations |
|---|---|
| Virginia / North Carolina / Georgia | Appalachian mountain localities – the most consistent U.S. region |
| Colorado | Beckwith Range (Gunnison), Wolf Creek Pass (Mineral County) |
| New Mexico | Rabb Canyon (Grant County), Jemez Mountains (Sandoval County), San Mateo District (Sierra County) |
| California | Funeral Range, Inyo County |
Florida is a special case – moonstone is the state’s official gemstone, but not because it’s found there naturally. The designation instead honors the state’s role in the U.S. space program, so a Florida rockhound shouldn’t expect to actually dig one up locally.
Recommendation box: All tools and equipment you need for rockhounding and rock identification* (Amazon links):
1. Estwing Rock Hammer – Light, comfortable, and extremely durable hammer.
2. Estwing Geologist Pick – Classic and the most trusted paleo pick in the world.
3. Finder 12-inch Chisels – Heavy-duty chisels set with hand protection.
4. Mini Handle Shovel – This is a great tool for digging deep in the dirt.
5 Ironclad Utility Work Gloves – Breathable, but they also protect the areas requiring them most.
6. 3M Safety Glasses – Comfortable and efficient goggles for rockhounding.
7. Convoy 8+ UV Light – 365nm UV LED flashlight with a patented glass filter.
8. Wesley’s Jewelers Loupe – High magnification options (30X and 60X) with carrying case.
9. Mohs Hardness Kit – A specially designed kit for rockhounds
*All recommended products are personally tested and regularly used by experts from this website.
For deeper background on the mineral’s optical properties and gemological grading, the Gemological Institute of America’s moonstone reference is a solid starting point, and the International Gem Society’s moonstone guide covers buying and care in more depth.
| Research Behind This Guide |
|---|
This guide was compiled and edited by the How to Find Rocks team. It consolidates, fact-checks, and builds on original research and field reporting first published on this site by the following subject-matter expert(s): Olena Rybnikova – Ph.D. candidate in Mineralogy and GIA Applied Jewelry Professional, with published research on the peer-reviewed portal Scopus. See all articles by Olena → |