Is Charoite UV Reactive?
Is charoite UV reactive? The one lamp test credits the glow to microcline and steacyite; lab work saw 585 and 705 nm under beams. What each source shows.
Not on a reliable record. The one fetched lamp test, a Fluorescent Mineral Society charoite slab under 365, 305 and 255 nm, credits its red glow to microcline and green to steacyite. A 2008 study measured strong charoite emission at 585 and 705 nm under electron and ion beams, not a lamp. No Handbook sheet exists.
In short
- The lamp test. The Fluorescent Mineral Society database, specimen 147 is a polished slab of purple charoite with aegirine, microcline and steacyite from the Murunskii Massif, Chara and Tokko Rivers confluence, Russia. Under longwave (365 nm), midwave (305 nm) and shortwave (255 nm) LEDs it lists two responses: microcline red, steacyite green. Charoite is not among them.
- The laboratory record. Garcia-Guinea and others (2008), Journal of Luminescence 128, 403–412 report charoite’s intense lilac colour related to Mn2+ and Fe3+ centres, and strong luminescence at about 585 and 705 nm, with weaker UV-blue emission at 340 and 390 nm. Their methods were thermoluminescence, cathodoluminescence and ion-beam luminescence, and they found the luminescence strongly heterogeneous in space. That is charoite glowing under beams and heat, not under a collector’s lamp.
- The grain rule. Charoite rock is a mix: IGS names tinaksite, microcline and aegirine-augite in it. On these sources a glow on a charoite piece is evidence about the grain it comes from. Credit it to charoite only where a source does; the one lamp test put it on two other minerals.
- Documented failure: the Fluomin record. The Fluomin charoite record lists shortwave red, but its comment describes a boron fluoro-silicate from near the Nadym River, Krasnoyarsk territory. The IMA formula for charoite has no boron, and IGS gives the Chara River area, Sakha Republic, as the only source. The record does not match charoite as the other sources describe it.
- No sheet, no IGS entry. The Handbook charoite PDF returned HTTP 404 on 6 November 2026. The IGS charoite panel has no luminescence entry; its phenomenon line, “some stones show a chatoyant glow”, is chatoyancy, a reflection effect. The dye question is answered on is charoite dyed.
| Source | Excitation | What glowed, as reported | Credited to charoite? | Caveat |
|---|---|---|---|---|
| Fluorescent Mineral Society, FMDB specimen 147 | UV LEDs at 365, 305 and 255 nm | Microcline red at all three; steacyite green at all three | No | XRD identified the microcline; steacyite identified as likely, citing mindat |
| Garcia-Guinea and others (2008), J. Luminescence 128 | Thermoluminescence, cathodoluminescence, ion beams (H+, H2+, He4+) | Strong emission at about 585 and 705 nm; weaker at 340 and 390 nm | Yes | Not a UV lamp; abstract read, paper body not fetched |
| Fluomin charoite record | Shortwave UV, 254 nm | Red | As listed | Comment describes a boron fluoro-silicate from near the Nadym River, Krasnoyarsk |
| International Gem Society charoite article | — | No luminescence entry; “some stones show a chatoyant glow” | No | Chatoyancy is reflection, not luminescence |
| Handbook of Mineralogy | — | No sheet | — | charoite.pdf HTTP 404, 6 November 2026 |
Does charoite glow under UV light? What the lamp test shows
In the one fetched lamp test, the charoite piece glowed, but the glow came from two other minerals in it. The Fluorescent Mineral Society database, specimen 147, contributed by Michael Crawford on 24 June 2025, is a 9 × 14.5 cm polished slab of purple charoite, black aegirine, white microcline, light brown tinkasite (so spelled there; the IMA list writes tinaksite) and steacyite from the Murunskii Massif, Chara and Tokko Rivers confluence, Aldan Shield, Russia. It says the microcline fluoresces red under all wavelengths of UV light, and that XRD identified the microcline; citing mindat, it says the scattered green grains are likely steacyite. Its summary lists microcline red and steacyite green under longwave (365 nm), midwave (305 nm) and shortwave (255 nm) LEDs, and lists nothing for charoite.
What that does and does not say. It does not say charoite is inert; it records no response for it. It does show that a charoite slab can show red and green under a lamp without charoite doing it. The September 2026 IMA-CNMNC Master List lists microcline, K(AlSi3O8), and steacyite, K0.3(Na,Ca)2ThSi8O20; the species page is microcline. The FMS gives ferric iron as the likely activator of the microcline’s red and uranium for the steacyite’s green; this page adds no activator claim of its own. Steacyite’s formula has thorium; radioactivity questions go to is my mineral radioactive, and nothing here is advice.
The grain rule. Read a glowing charoite piece grain by grain. The International Gem Society charoite article says the rock is almost purely charoite but can include orange tinaksite, pale greenish grey microcline and greenish black aegirine-augite. A red spot may be the microcline. Credit a glow to charoite only where a source does.
Is charoite fluorescent at all? The laboratory evidence
Yes, under laboratory excitation: Garcia-Guinea and others measured strong charoite luminescence at about 585 and 705 nm. Their 2008 paper in the Journal of Luminescence, volume 128, pages 403 to 412, studied charoite by thermoluminescence of pre-heated and pre-irradiated aliquots, time-resolved cathodoluminescence, cathodoluminescence under a scanning electron microscope, and ion-beam luminescence with H+, H2+ and He4+ ions. The abstract links the 585 nm peak to Mn2+ and the 705 nm emission to iron, and reports weaker UV-blue emissions at 340 and 390 nm. It also reports that the luminescence is strongly heterogeneous in space. The abstract, from the Garcia-Guinea and others (2008), Journal of Luminescence 128, 403–412 record, is what was read; the paper body was not fetched.
Why that is not a lamp answer. None of those methods is a handheld ultraviolet lamp, and the abstract reports no UV-lamp measurement. It shows charoite has luminescence centres; it does not say what a collector will see under a lamp. Apart from the Fluomin entry below, no fetched source reports charoite itself under a lamp.
Documented failure: the Fluomin record. The Fluomin charoite record gives shortwave (254 nm) red for charoite, with Mn2+, Ce3+ and Eu2+ as activators citing Gaft. Its comment, though, describes fluorescence reported in the violet gem variety of a boron fluoro-silicate from near the Nadym River, Krasnoyarsk territory. The IMA formula, (K,Sr,Ba,Mn)15-16(Ca,Na)32[Si70(O,OH)180](OH,F)4·nH2O, has no boron, and IGS names the Chara River area as the only source. The record may be about a different material; this page does not rely on it.
What the gem sources say about charoite under UV
Nothing: the IGS charoite panel has no luminescence entry, and there is no Handbook sheet. The International Gem Society charoite article panel lists absorption spectrum, birefringence 0.009, cleavage fair to good, hardness 5 to 6, RI 1.550 to 1.559, specific gravity 2.54 to 2.78 and phenomena, but no luminescence line, where other IGS panels, such as phenakite’s, carry one. Its phenomena line, “some stones show a chatoyant glow”, is chatoyancy, light reflected from fibres, not luminescence.
No Handbook sheet. handbookofmineralogy.org/pdfs/charoite.pdf returned HTTP 404 on 6 November 2026, as it did in run 33, so there is no sheet wording to quote. The IMA list has charoite as a species, status A, 1977-019, Russia. The figures on is charoite dyed are IGS’s and agree with those here: a 20.00 g charoite reads 12.13 to 12.81 g in water at IGS’s SG. Charoite as a rock named for its mineral, like lapis lazuli, is on is lapis lazuli a mineral or rock.
How to read a charoite piece under a lamp, and what not to conclude
Note where the glow sits, not just its colour. On the FMS slab the red was in the white microcline and the green in scattered grains of steacyite, the largest 2 mm long. That record ties each colour to a grain, not to the rock as a whole. How longwave and shortwave lamps differ is on best UV lamp for mineral collecting and fluorescent minerals explained; another worked case where the sources and the sheet disagree is is celestite UV reactive.
What not to conclude. A glow does not prove a piece is charoite, and no glow does not prove it is not: no fetched source gives charoite a diagnostic lamp response. Identification on this site rests on the numbers on is charoite dyed. Exposure limits for ultraviolet radiation from 180 to 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 guides are in the collecting guides. We hold no catalogue and nothing here is offered for sale; the wanted list is the only commercial route.