Short answer: angelite is a trade name for translucent blue-gray anhydrite, an anhydrous calcium sulfate (CaSO4), first marketed from Peru in the late 1980s. It is not celestite, which is strontium sulfate and noticeably heavier. Angelite is soft (Mohs 3 to 3.5), splits along three cleavages at right angles, and slowly absorbs water to become gypsum, so it should be kept dry and never left soaking.
Is angelite celestite or anhydrite?
Anhydrite. The confusion is understandable: both minerals are pale blue sulfates, both crystallize in the orthorhombic system, and both turn up in the same evaporite settings. Many sellers repeat the claim that angelite is "compressed celestite", but the chemistry does not support it. The International Gem Society describes angelite as a "translucent, blue-gray anhydrite variety" known by the trade names angelite or angeline, discovered in Peru and introduced to world markets in the late 1980s (International Gem Society). Minerals.net lists angelite as the nodular, polished form of anhydrite (Minerals.net).
The difference is the metal in the formula. Celestite carries strontium; anhydrite carries calcium. That one swap changes the weight of the stone enough to feel in the hand, which makes it the most useful test a buyer has.
| Property | Anhydrite (angelite) | Celestite | Gypsum (selenite) |
|---|---|---|---|
| Formula | CaSO4 | SrSO4 | CaSO4·2H2O |
| Crystal system | Orthorhombic | Orthorhombic | Monoclinic |
| Mohs hardness | 3 to 3.5 | 3 to 3.5 | 2 |
| Specific gravity | 2.9 to 3.0 | 3.9 to 4.0 | 2.3 |
| Typical blue form sold | Massive nodules, tumbles, spheres | Crystal clusters, geodes | Rarely blue |
Figures from Geology.com, Minerals.net and Geology.com on gypsum.
What is anhydrite, mineralogically?
Anhydrite is calcium sulfate without water. Its name comes from the Greek anhydros, "waterless", a deliberate contrast with gypsum, which holds two water molecules in its structure (Webmineral). Webmineral gives a measured density of 2.96 to 2.98, with calcium making up 29.44 percent of the mineral by weight.
The feature that identifies anhydrite in the field is its cleavage. It breaks in three directions at right angles, so broken pieces look like little blocks, and old collectors called it "cube spar" for that reason. Under a loupe, a fine-grained piece shows a sugary sparkle on broken surfaces where countless tiny cleavage faces catch the light. Despite the cube-like fragments, anhydrite is not cubic; the crystals are orthorhombic, and cubic-looking pieces are a product of the cleavage, not the crystal shape.
Angelite is the massive form: no visible crystals, just a dense, waxy to pearly blue-gray body that takes a soft polish. That is why angelite is sold as tumbles, palm stones, spheres and beads rather than as clusters. If a listing shows sharp, glassy blue blades on a matrix, it is far more likely celestite than angelite.
How does anhydrite form, and where does angelite come from?
Most anhydrite is an evaporite. It forms in thick layered deposits in sedimentary basins where large volumes of seawater evaporated, interbedded with halite, gypsum and limestone, and those beds can be hundreds of feet thick (Geology.com). It also fills hydrothermal veins and occurs in the cap rock above salt domes.
Commercial angelite is tied to Peru. Other blue anhydrite reaches collectors from elsewhere: Minerals.net singles out the light blue, dense fibrous veins from the mines at Naica, Chihuahua, Mexico, as some of the best anhydrite on the market, and notes white and lilac crystals found in the Simplon Tunnel in Switzerland during the construction of a railroad tunnel. Those Mexican and Swiss pieces are specimen material; the Peruvian nodules are what fill bowls of angelite tumbles.
Why does angelite turn white or crumble when it gets wet?
Because water is slowly rebuilding it into gypsum. Geology.com notes that anhydrite "readily converts to gypsum under humid conditions or in contact with groundwater", and that the change involves a significant increase in volume. In nature that swelling can deform whole rock units. On a polished stone it shows as a dull, chalky skin, loss of polish, and in bad cases fine cracks that open as the surface expands.
The International Gem Society's care advice is blunt: keep anhydrite dry, especially in storage, because it will absorb moisture and turn wholly or partly into gypsum over time. It also warns against wiping dust off, since household dust is mostly quartz, hardness 7, and will scratch a stone that rates only 3 to 3.5. Pat it with a lint-free cloth instead.
In practice:
- Do not soak angelite, rinse it under a tap, or leave it in a bowl of water or in a bathroom.
- Do not put it in salt; salt draws moisture and leaves residue.
- Store it with other soft stones in a dry room, away from humidifiers and windowsills that collect condensation.
- If it gets wet, blot it at once and let it air dry; brief contact is not fatal, prolonged contact is.
Our planned guide to humidity-sensitive minerals covers storage for this whole group.
How can you tell angelite from celestite, blue calcite or dyed stones?
Weight in the hand
Celestite has a specific gravity of 3.9 to 4.0, against 2.9 to 3.0 for anhydrite. Two tumbles of the same size will differ by roughly a third in weight. A kitchen scale and a cup of water give a rough specific gravity at home, but you need not go that far: hold a known celestite piece in one hand and the suspect stone in the other.
Acid reaction
Anhydrite does not react with acid, while calcite and marble fizz. The International Gem Society suggests this as a way to separate carved anhydrite from marble, but warns it is destructive and should be a last resort on a hidden spot. Most buyers never need it; blue calcite usually shows rhombic cleavage and a glassier, more transparent look.
Cleavage and hardness
Look at chips and edges. Steps at right angles point to anhydrite. Gypsum is softer (Mohs 2) and can be scratched with a fingernail edge, while anhydrite resists a fingernail but yields to a copper coin or steel.
Color behavior
The International Gem Society reports that blue and violet colors in anhydrite disappear when the stone is heated and return after gamma irradiation, which suggests the color comes from natural radiation in the ground. Natural specimens are not radioactive. The practical point: never put angelite near a flame, a hot lamp or a jeweler's torch.
Other anhydrite names a buyer may see
Angelite is the best-known trade name for anhydrite, but not the only one. The International Gem Society lists bowel stone for folded, concretionary anhydrite and vulpinite for a white-gray, marble-textured anhydrite from Volpino, Italy. Ancient Egyptians carved both white and blue anhydrite; a Brooklyn Museum kohl pot of about 1938 to 1700 BCE is cut from it, and the source of that blue material has never been found.
What is angelite traditionally associated with?
In crystal traditions, angelite is associated with calm communication and is often paired with the throat chakra; the name itself was chosen for its "heavenly" blue. These are traditions, not measurable properties.
What to look for when you buy angelite
Angelite is inexpensive, and the main risks are mislabeling and poor care, not fakes. Check that the color is an even, soft blue-gray with faint white veining, that the polish is satin rather than glassy, and that there is no chalky white bloom, which signals a stone that has been stored damp. Ask whether a "celestite" sphere might really be anhydrite; at that weight difference a seller with a scale can settle it in seconds.
- Angelite Tumbles: small polished pieces of the blue anhydrite itself, the easiest way to feel its lighter weight and satin luster.
- Celestite Crystal Cluster on Matrix: the mineral angelite is mistaken for, in its natural crystal form; useful as a comparison piece for the weight test.
- Celestite Part Polished: a celestite piece with a worked face, close in look to massive blue anhydrite and a good side-by-side study.
- Selenite Sphere 6cm: gypsum, the hydrated calcium sulfate that angelite becomes when it takes on water; softer and lighter still.
- Desert Rose: gypsum rosettes grown in sand, another evaporite sulfate from the same chemical family.
Digital Towns Market
Angelite in stock
Frequently asked questions
Is angelite the same as celestite?
No. Angelite is anhydrite, calcium sulfate, while celestite is strontium sulfate. They share a pale blue color and orthorhombic crystals, but celestite is about a third heavier for the same size, with a specific gravity near 4.0 against about 2.97 for anhydrite.
Can angelite go in water?
Avoid it. Anhydrite absorbs water and slowly converts to gypsum, which swells and leaves a dull, chalky surface. A quick splash blotted dry does little harm, but soaking, rinsing under a tap or storing it in a humid room will degrade the polish over time.
Where is angelite found?
Commercial angelite comes from Peru, where it was discovered and from where it entered world markets in the late 1980s. Blue anhydrite also comes from Naica in Chihuahua, Mexico, but that material is usually sold as mineral specimens rather than as angelite.
How hard is angelite?
Angelite rates 3 to 3.5 on the Mohs scale, so a steel blade or even household dust can scratch it. It is fine for pendants and display pieces but poor for rings, and it should be stored apart from quartz and other harder stones.
Is angelite dyed?
The soft blue-gray color of angelite is natural and is thought to come from natural radiation in the ground. Heat removes it. Be wary of strongly saturated or uneven blue color in very cheap beads, and ask the seller what the material is.
Sources
- International Gem Society, Anhydrite (Angelite) Value, Price, and Jewelry Information: https://www.gemsociety.org/article/anhydrite-jewelry-and-gemstone-information/
- Geology.com, Anhydrite: https://geology.com/minerals/anhydrite.shtml
- Minerals.net, The mineral anhydrite: https://www.minerals.net/mineral/anhydrite.aspx
- Webmineral, Anhydrite Mineral Data: https://webmineral.com/data/Anhydrite.shtml
- Minerals.net, The mineral celestine: https://www.minerals.net/mineral/celestine.aspx
- Geology.com, Gypsum: https://geology.com/minerals/gypsum.shtml
- International Gem Society, Celestite Value, Price, and Jewelry Information: https://www.gemsociety.org/article/celestite-jewelry-and-gemstone-information/