Angelite Identification Guide
How to identify angelite, the pale blue gem variety of anhydrite, by its low hardness, color, and the tests that separate it from celestite and howlite.
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What Angelite Looks Like
Angelite is a trade name for the pale blue-gray gem variety of anhydrite (calcium sulfate, CaSO4). It is soft, opaque, and a soothing light blue to lavender-blue or blue-gray, sometimes with white patches or fine reddish-brown veins. Luster is dull to slightly pearly or waxy, never glassy or sparkly. It is typically sold as tumbled stones, beads, and carved pieces rather than crystals, because the massive material takes a smooth matte polish.
Step-by-Step Field-ID Checklist
- Note the soft powder-blue color with a matte, slightly chalky surface.
- Test hardness — angelite is soft (Mohs ~3.5); a steel knife or even a copper coin marks it easily, and it can be scratched with a fingernail-hard point with effort.
- Check opacity and luster — opaque with a dull-to-waxy, not vitreous, surface.
- Look for veining — fine white or rusty veins are common.
- Keep it dry — anhydrite slowly converts toward gypsum with prolonged water contact, so soaking can damage it (a behavioral clue).
Key Diagnostic Tests
- Mohs hardness: ~3–3.5 — easily scratched by a knife.
- Streak: white.
- Cleavage: anhydrite has three cleavages at right angles, though massive angelite often shows uneven fracture.
- Specific gravity: ~2.9–3.0.
- No effervescence in acid (distinguishes the sulfate from carbonates like calcite).
- Soluble/reactive to prolonged water — slowly alters to gypsum.
Common Look-Alikes
- Howlite (dyed blue): howlite is white with gray web-like veining and is often dyed; dyed-blue howlite can mimic angelite but has more pronounced spidery dark veins and slightly different texture. A scratch in dyed material may reveal white beneath.
- Celestite (celestine): strontium sulfate, similar pale blue, but usually found as glassy transparent crystals rather than opaque massive stone; celestite is denser (SG ~3.9–4.0).
- Blue calcite: softer is not the test here — calcite fizzes in acid, anhydrite does not.
- Larimar: blue pelletal patterns and harder (Mohs ~4.5–5); larimar shows distinctive white-and-blue mottling and takes a higher polish.
- Turquoise: harder (Mohs 5–6), greener-blue, and does not soften in water.
Where It Is Found
Anhydrite forms in evaporite deposits (where seawater or salt lakes dried up) and in association with gypsum and halite, as well as in some hydrothermal and cap-rock settings. The blue 'angelite' material is mined principally in Peru, with anhydrite occurring widely in evaporite basins in Mexico, the U.S., Germany, and elsewhere.
Frequently asked questions
How can you tell if angelite is real?
Real angelite is anhydrite: soft (Mohs ~3.5, scratched by a knife), opaque pale blue-gray with a dull-to-waxy surface, does not fizz in acid, and slowly reacts with prolonged water. Dyed howlite imitations show white beneath a scratch and spidery dark veins.
What does angelite look like?
It is an opaque, soft, powder-blue to lavender-blue stone with a matte or slightly pearly finish, often with white areas or fine rusty veins, usually sold as tumbled stones, beads, or carvings.
Angelite vs howlite — what's the difference?
Both are soft and pale, but angelite is naturally blue anhydrite, while howlite is naturally white with gray web veining and is frequently dyed blue to imitate other stones. Howlite's veining is more spidery and a scratch may reveal white.
Can angelite get wet?
Avoid prolonged water exposure. Angelite is anhydrite (calcium sulfate) and slowly converts toward gypsum and can degrade when soaked, so it should be kept dry and cleaned only briefly.
Angelite identified by the community
Recent Angelite specimens identified with Rock Identifier.
