Is scapolite fluorescent
Scapolite is a group, not a species. Both its sheets say it commonly fluoresces orange to bright yellow or red, LW or SW; 3 of 31 fluorescent sheets say that.
Often, by its reference's own wording. Scapolite is the group name for marialite and meionite, and both Handbook of Mineralogy sheets say they commonly fluoresce orange to bright yellow or red under LW or SW UV or both. Only three of the 31 fluorescent sheets among the 176 in this site's reference set say commonly. Hardness is 5 to 6.
In short
- Yes, more reliably than most. The marialite and meionite sheets carry the same sentence: Commonly fluoresces orange to bright yellow or red under LW or SW UV or both. Both bands, three colours, and the word commonly.
- Commonly is rare language in the reference. Of 31 sheets in this site's 176-sheet set that record fluorescence, 18 say may, 8 state it without qualification, one says rarely, one says typically, and three say commonly: marialite, meionite and natrolite.
- Scapolite is not a species. The word does not appear on the September 2026 IMA list. The valid species in the group include marialite, meionite and silvialite, and the Handbook says most specimens are intermediate between the first two.
- It is not a quartz and not a feldspar, but the feldspar question is a good one: the Handbook writes marialite as three albite units plus sodium chloride, and meionite as three anorthite units plus calcium carbonate.
- Neither sheet records radioactivity, toxicity or pleochroism. Those questions are answered below from what the sheets do say, and nothing on this page gives a price.
| Species | Formula as the Handbook writes it | System | Hardness | Density | Fluorescence as recorded |
|---|---|---|---|---|---|
| Marialite | 3NaAlSi3O8·NaCl | Tetragonal | 5.5 to 6 | 2.50 to 2.62 | Commonly orange to bright yellow or red, LW or SW or both |
| Meionite | 3CaAl2Si2O8·CaCO3 | Tetragonal | 5 to 6 | 2.74 to 2.78 | Commonly orange to bright yellow or red, LW or SW or both |
| Albite, a feldspar | NaAlSi3O8 | Triclinic | 6 to 6.5 | 2.60 to 2.65 | Nothing recorded |
| Anorthite, a feldspar | CaAl2Si2O8 | Triclinic | 6 to 6.5 | 2.74 to 2.76 | Nothing recorded |
| Microcline, a feldspar | KAlSi3O8 | Triclinic | 6 to 6.5 | 2.54 to 2.57 | Nothing recorded |
| Quartz | SiO2 | Hexagonal, point group 32 | 7 | 2.65 | Nothing recorded; may be triboluminescent |
| Natrolite | Na2Al2Si3O10·2H2O | Orthorhombic | 5 to 5.5 | 2.20 to 2.26 | Commonly orange to yellow, no band named |
Is scapolite fluorescent? What the two sheets say, and how rare that wording is
Method. Every one of the 176 Handbook of Mineralogy sheets in this site's reference set was converted with pdftotext and each sentence containing uoresc extracted by regular expression; the truncated string catches older sheets where fl is set as a ligature, which includes both scapolite sheets. Each sentence was then classified by its qualifier.
Result. 31 sheets record fluorescence. 18 say may. 8 state it without a qualifier, fluorite and hydrozincite among them. One says rarely, halite. One says typically, willemite. Three say commonly: marialite, meionite and natrolite. The two scapolite end-members carry identical sentences, word for word.
What the wording tells a collector. May means some specimens and not others. Commonly is a stronger statement, and the scapolite sheets also name both bands, which 12 of the 31 fluorescent sheets do not. So a scapolite that stays dark under a lamp is the less expected result, though not an impossible one. The general mechanism is on fluorescent minerals explained.
Scapolite is a group name, not a species
The September 2026 IMA-CNMNC list contains no entry called scapolite. The group's species on it include marialite, Na4Al3Si9O24Cl, grandfathered with an Italian type locality dated 1866; meionite, Ca4Al6Si6O24(CO3), grandfathered, Italy, 1801; and silvialite, Ca4Al6Si6O24(SO4), approved in 1998 from Australia. This site's reference set holds sheets for the first two only.
The Handbook states the practical consequence directly: most specimens are intermediate in the series. A label reading scapolite is therefore usually the honest label, because telling where a given crystal sits between marialite and meionite takes an analysis, not a hand lens. The nomenclature in full is on the scapolite page.
Is scapolite a feldspar? No, but its formula is written as one
The Handbook writes marialite as 3NaAlSi3O8·NaCl: three formula units of albite plus one of sodium chloride. It writes meionite as 3CaAl2Si2O8·CaCO3: three of anorthite plus one of calcium carbonate. Multiply out and you get the IMA formulas exactly. Scapolite is a feldspar composition with a salt locked inside a different framework, and it turns up where the Handbook says it does: marbles, calcareous gneisses, granulites and skarns.
The framework is the difference. Scapolite is tetragonal, with distinct cleavage on {100} and {110}; the feldspars in the table are triclinic, with perfect cleavage on {001}. Hardness overlaps at 6 and density overlaps across 2.5 to 2.8, so neither test separates them. Both sheets describe prismatic crystals striated along their length, typically with flat pyramidal terminations, which is the habit to look for. How to recognise the feldspars themselves is on how to identify feldspar.
The rest of this section is indexed at the collecting guides. Nothing on this site is offered for sale; the wanted list is the only commercial route.