Is aragonite fluorescent?
Yes. The Handbook sheet says red or yellow under longwave and shortwave UV, phosphorescent; in 64 FMS records white is commonest, red or yellow in 13 of 64.
Yes, usually. The Handbook aragonite sheet says fluorescent red or yellow under longwave and shortwave UV, and phosphorescent. But all 64 Fluorescent Mineral Society records of aragonite list a glow, most often white: 37 of 59 shortwave records; red or yellow appear in 13 of 64. Calcite glows too, so a UV lamp does not identify aragonite.
In short
- The sheet says yes, without a may. The Handbook of Mineralogy aragonite sheet reads: Cathodoluminescent, fluorescent red or yellow under LW and SW UV, phosphorescent. Aragonite is Ca(CO3) on the IMA-CNMNC Master List, hardness 3.5 to 4, density 2.95. The calcite sheet hedges with may fluoresce red, blue, yellow and other colours; that comparison is on is calcite UV reactive, not repeated here.
- The 64-record colour check. The Fluorescent Mineral Society database (FMDB) aragonite records held 64 aragonite records on 10 November 2026, and every one lists aragonite fluorescence: under shortwave in 59, longwave in 32, midwave in 15. White is the commonest colour, 37 of 59 shortwave records; pink comes next under longwave (7 of 32 lines). Red or yellow, the sheet’s two colours, appear in 13 of 64 records.
- Phosphorescence is common in the records too. 23 of the 64 list an aragonite afterglow: green after longwave on 13 of 14 lines, blue after shortwave on 9 of 14. The Fluomin aragonite record gives greenish white phosphorescence under all three bands, strong and often, and rates the fluorescence strong and very often under longwave, medium and very often under shortwave.
- Documented failure: a green glow may not be the aragonite. Modreski (1987, New Mexico Geology) writes that calcite and aragonite have often been described as exhibiting a green fluorescence, but in all of the samples he examined, from New Mexico, Arizona, California, Colorado, Washington and Mexico, it was localized in thin layers of opal on the surface of the carbonate or intergrown with it. And 35 of the 64 FMDB records list more than one mineral, so the colour credited to aragonite is the contributor’s call.
- What a lamp can and cannot do. A glow says the piece is luminescent; it does not say aragonite: calcite’s sheet records red, blue, yellow and other colours under both bands, and in the FMDB’s Agrigento record celestine on aragonite glows white too. Identification is on is aragonite the same as calcite. UV exposure limits are in the ICNIRP 2004 guidelines on limits of exposure to ultraviolet radiation; this is not safety advice.
| Band | Records with aragonite fluorescence | Fluorescence lines by colour | Red or yellow (the sheet’s colours) | Afterglow lines | Handbook sheet |
|---|---|---|---|---|---|
| Shortwave (254 nm lamp, 255 nm LED) | 59 of 64 | White 37, blue 10, green 7, violet 3, red 2, yellow 1 | 3 of 60 lines | 14: blue 9, white 4, green 1 | Red or yellow |
| Longwave (365 nm LED or lamp) | 32 of 64 | White 13, pink 7, red 6, yellow 4, green 1, blue 1 | 10 of 32 lines | 14: green 13, blue 1 | Red or yellow |
| Midwave (305 nm) | 15 of 64 | White 6, pink 5, yellow 2, green 1, red 1 | 3 of 15 lines | 2: blue 1, yellow 1 | Not mentioned |
| Any band | 64 of 64 | — | 13 of 64 records | 23 of 64 records | Phosphorescent; cathodoluminescent |
| Fluomin record 87 (for comparison) | — | LW, MW, SW: white, bluish, pink, salmon, orange, red and others | Orange red and red listed in all three | Greenish white, all three bands, strong, often | — |
Does aragonite glow under UV light? What the sheet says
The wording. Under Physical Properties the aragonite sheet prints, after hardness and density: Cathodoluminescent, fluorescent red or yellow under LW and SW UV, phosphorescent. It names both bands and does not qualify the statement with may. The search that confirms the wording is ligature-aware: on older sheets pdftotext turns the fl ligature into a stray glyph, so the stem uoresc is searched, case-insensitively, and the hemimorphite and willemite sheets have to match as positive controls. Here the aragonite sheet prints the word in plain text.
What it does not say. The sheet gives no share of specimens that glow, no colour other than red or yellow, and no cause. aragonite is Ca(CO3) on the September 2026 IMA list, orthorhombic, hardness 3.5 to 4, density 2.95; is aragonite a polymorph of calcite covers its relation to calcite and vaterite.
What 64 lamp records show
Method. The FMDB aragonite page linked 64 specimen records on 10 November 2026; all 64 were saved and read by script. Each record’s Summary of luminescence responses has a block per mineral; the script took the aragonite block and tallied its lines by kind (fluorescence or afterglow), band and colour. Contributions are dated 2024 (1), 2025 (11) and 2026 (52); localities run from the USA (21) and Italy (14) to Canada, Mexico, Greece, Spain, Belgium, France, Morocco and New Zealand.
Result. Every record lists aragonite fluorescence in at least one band: shortwave in 59, longwave in 32, midwave in 15. The commonest colour is white, in 37 of the 59 shortwave records; under longwave the lines run white 13, pink 7, red 6, yellow 4, green 1, blue 1. 23 records list an afterglow. The FMDB descriptions also offer causes for some responses; this page does not repeat them. Four titles appear twice, which may be separate specimens; the counts treat each record as one.
The sheet-colour check: red or yellow in 13 of 64
The check. The sheet gives two colours, red or yellow. Counting any fluorescence line that contains red or yellow, 13 of the 64 records qualify: 10 of 32 longwave lines, 3 of 60 shortwave lines and 3 of 15 midwave lines. Pink, the second longwave colour, is counted separately. So the sheet’s colours are the longwave minority, and under shortwave they are rare in this database, where white dominates.
How to read it. The FMDB is a collectors’ database of chosen specimens, not a random sample, and a record is the contributor’s description. The result is a range, not a frequency for aragonite in general: a white shortwave glow is the commonest record, a red or yellow one is in the sheet, and the Fluomin aragonite record lists both. A dark specimen is not ruled out as aragonite, because none of the sources gives a share that stay dark.
Green glows and mixed specimens: where the check fails
Opal. Modreski (1987, New Mexico Geology) says green fluorescence in calcite and aragonite has often been described, but in every sample he examined it sat in thin layers of opal on the surface of the carbonate or intergrown with it. Of the 64 FMDB records, seven shortwave lines and one longwave line credit aragonite with green; on Modreski’s evidence a green glow on a white carbonate deserves a second look before it is written on a label.
Combinations. 35 of the 64 summaries list more than one mineral, for example celestine on aragonite from Agrigento, where the record gives aragonite pink under longwave and celestine white. The aragonite sheet names the Passaic mine, Sterling Hill, in the Franklin and Sterling Hill district. Under one lamp the colours of neighbours can overlap; celestine’s own records are on is celestite UV reactive.
Aragonite, calcite and coral under the lamp
Calcite. Calcite is the same Ca(CO3) and fluoresces in overlapping colours, so the lamp cannot choose between them; the decision rule is on is aragonite the same as calcite and the sheet survey on is calcite UV reactive. Coral skeletons are aragonite according to the USGS; whether coral-derived aragonite glows is not addressed by any source fetched here, and the coral question itself is on is aragonite crushed coral.
Lamps and safety, in one line. Use both bands and note each result with the locality; a longwave-only lamp leaves the shortwave result, where most of the records lie, untested. Lamp types are compared on the best UV lamp for mineral collecting and the physics is on fluorescent minerals explained. UV exposure limits between 180 and 400 nm are in the ICNIRP 2004 guidelines on limits of exposure to ultraviolet radiation; this page is not safety advice, and other hazards are routed to toxic minerals in a collection. More in the collecting guides. We hold no catalogue and nothing here is offered for sale; the wanted list is the only commercial route.