Uvite
Uvite is a calcium-magnesium tourmaline, hardness 7.5, crystals to 15 cm. The name was reassigned in 2022, so most older uvite labels now describe fluor-uvite.
Uvite is a calcium-magnesium tourmaline, hardness 7.5, density 2.97 to 3.14, in prismatic to equant crystals to 15 cm with the curved triangular cross-section of the group. The name was reassigned by the IMA in 2022, and most labels written before then describe what is now called fluor-uvite.
In short
- The name has moved, and this is the single most useful thing to know about the species. The IMA-CNMNC list now gives uvite as an approved species of 2019, with Italy as the country of first description and a hydroxyl-dominant formula. The fluorine-dominant analogue, fluor-uvite, carries the 1930 original reference and Sri Lanka as its country.
- The 1977 Mineralogical Record paper that made uvite a collector name is cited by the IMA under fluor-uvite, not under uvite. That paper introduced the species to collectors and is the reason the name is on so many labels at all.
- Do not relabel a specimen on this basis. Which of the two a given crystal is depends on whether fluorine or hydroxyl dominates one site, and that is an analytical question. The defensible catalogue entry records the label as written and notes that the name was redefined.
- Hardness 7.5 puts it above quartz. Tourmaline is one of the few collection species that will scratch a quartz crystal, and that is a fast field separation from the brown calcites and micas it sits with in marble.
- The habit is the group's signature. Cross-sections are typically triangular with curved, convex sides. It may fluoresce a weak mustard-yellow under shortwave ultraviolet, and it is pyroelectric and piezoelectric.
| Name | IMA status | Year | Country of first description | What it means on a label |
|---|---|---|---|---|
| Uvite | Approved (2019-113) | 2022 reference | Italy | The hydroxyl-dominant species, as redefined |
| Fluor-uvite | Redefined | 2011, from a 1930 description | Sri Lanka | Carries the original Uva Province material |
| Feruvite | Approved (1987-057) | 1987 | New Zealand | The iron analogue; darker, usually black |
| Dravite | Grandfathered | — | Austria (Drave district) | The sodium-magnesium tourmaline, not calcium |
| Elbaite | Grandfathered | — | Italy (Elba) | The lithium tourmaline; the coloured gem material |
| Schorl | Grandfathered | — | Germany | The common black iron tourmaline |
What actually changed, and what your label now means
Uvite was described as a distinct member of the tourmaline group on material from Uva Province, Sri Lanka, which is where the name comes from. The Handbook of Mineralogy's entry, published in 2001, gives that composition and that type locality, and the 1977 paper in the Mineralogical Record by Dunn and co-workers — Uvite, a new (old) common member of the tourmaline group and its implications for collectors — is what put the name into circulation among collectors.
The tourmaline group has since been reorganised, and the current IMA-CNMNC list of valid mineral species records two names where collectors used one. Fluor-uvite is listed as a redefined species, with Sri Lanka as its country and the 1930 Chemie der Erde description as its first reference — and with that 1977 Mineralogical Record paper as its second reference. Uvite is listed separately as an approved species with the number 2019-113, Italy as its country, and a 2022 paper in Mineralogical Magazine as its reference.
In plain terms: the name uvite now denotes the hydroxyl-dominant member, and the material that made the name famous sits under fluor-uvite. A label reading “uvite” written before 2022 is not wrong — it was correct under the nomenclature of its day — but it does not mean what the same word means now.
Why you should not go through the drawer relabelling
The temptation, on learning this, is to write “fluor-uvite” on every uvite label in the collection. Resist it.
The distinction between the two turns on whether fluorine or hydroxyl dominates a single site in the structure. You cannot see it, weigh it, scratch it or test it. It needs a chemical analysis, and most collection specimens have never had one. A relabelling exercise based on probability converts a known unknown into a false certainty, which is the worse of the two states to leave a specimen in — the same argument we make about the zeolite suffixes on heulandite.
The convention that survives scrutiny has three parts: record the label as written, in quotation marks if it is an old hand; record the current species name as undetermined between uvite and fluor-uvite; and record why. That is three fields in a catalogue, it costs nothing, and it is reversible if the specimen is ever analysed. Our cataloguing conventions set out the three-state convention in full.
The quotable version: a nomenclature change tells you what a name means, not what your specimen is.
Where the material comes from, and what a good specimen looks like
The Handbook's distribution list for the material described as uvite runs: Uva Province in Sri Lanka; the Sagaing district in Myanmar; Franklin and Hamburg in Sussex County, New Jersey; Gouverneur, Pierrepont and DeKalb in St Lawrence County, New York, and Horicon in Warren County; East Hampton in Middlesex County, Connecticut; Brumado in Bahia, Brazil; and Hnúšťa in Slovakia.
For most collectors the species is a Brumado mineral. The Bahia magnesite deposits produce lustrous brown to green crystals on white magnesite and dolomite, and the contrast between a dark tourmaline prism and a white carbonate matrix is what makes the specimens. The Handbook lists the association as calcite, dolomite, tremolite, apatite and scapolite, and gives the occurrence as calcium-rich rocks subjected to contact metamorphism and metasomatism that added boron — which is exactly the Brumado setting.
Crystals reach 15 cm. In practice a good collector specimen is a few centimetres of sharp, undamaged, terminated prism sitting on contrasting matrix, and the things that separate a good one from an ordinary one are termination, lustre and whether the crystal is complete on the back. Colour runs brown, light to dark green, red and black, and may be zoned parallel to the prism faces.
Hardness 7.5, and what that buys you
Tourmaline at 7.5 is one of the few species in a general collection harder than quartz, and that is a genuinely useful field fact rather than a statistic. A tourmaline prism will scratch a quartz crystal; a quartz crystal will not mark the tourmaline. On a marble or carbonate matrix, where the associates are calcite at 3, dolomite at 3.5 to 4 and apatite at 5, the hardness alone separates the tourmaline from everything around it.
It also means uvite is a robust species to own. It has no cleavage — the Handbook records fracture as uneven to conchoidal, and brittleness as its only mechanical weakness. That combination of hardness 7.5 and no cleavage puts it at the easy end of storage: it does not fade, it does not react to humidity, and it does not part. The risk is chipping a termination through careless handling, not deterioration. Compare that with the copper sulphates and arsenates on this site, which need an environmental regime. The practical consequences are on handling and storage, and tourmaline material we are looking for is on the wanted list.