Scorzalite
Scorzalite, Fe2+Al2(PO4)2(OH)2: the iron end of the lazulite series, described in 1949 from Brazil. Dark blue, massive, hardness 6, density 3.33, biaxial (−).
Scorzalite is the iron end of the lazulite series: Fe2+Al2(PO4)2(OH)2 on the IMA list, status G, described in 1949 from Brazil. Its Handbook sheet gives dark blue massive material to 7 cm, hardness 6, density 3.33, biaxial (−), α 1.626 to 1.645. The name applies where the Fe:Mg ratio exceeds 50:50 (Pecora and Fahey, 1950).
In short
- Two ways of writing it. The September 2026 IMA-CNMNC Master List writes the end member, Fe2+Al2(PO4)2(OH)2, status G, 1949, Brazil, with the 1949 American Mineralogist paper as first reference. The Handbook of Mineralogy sheet writes (Fe2+,Mg)Al2(PO4)2(OH)2, with magnesium written into the formula. The end member is 16.73% iron by mass; its ideal oxides, FeO 21.53, Al2O3 30.55, P2O5 42.53, H2O 5.40, sit within 0.04 of the column Pecora and Fahey printed in 1950.
- The Corrego Frio check. The sheet prints analysis (1) from the Corrego Frio mine, Brazil, as (Fe2+0.66 Mg0.34 Zn0.01)Σ1.01 (Al1.93 Fe3+0.02)Σ1.95 (PO4)1.94 (OH)2.08. Worked from its oxide weights with phosphorus at the printed 1.94, iron, magnesium, zinc and ferric iron reproduce (0.658, 0.337, 0.007, 0.022). Aluminium comes out 1.943, not 1.93, and hydroxyl 2.09, not 2.08. Basis-free, the oxides give 1.002 Al per P; the printed formula gives 0.995.
- The 3.32 check. The printed cell (a 7.15, b 7.31, c 7.25 Å, β 120°35′, Z = 2) has a volume of 326.22 ų. On it the pure iron end member gives 3.398, the sheet’s own Corrego Frio composition 3.289, and Fe0.76Mg0.24 gives 3.321. That is the Mg:Fe 24:76 of Pecora and Fahey’s Victory mine, South Dakota, sample, which they measured at 3.327: the sheet’s 3.32 and 3.33 match it, not the analysis the sheet prints.
- Documented failure: dark blue does not name it. The sheet prints dark blue; Pecora and Fahey, American Mineralogist 35 (1950) found California lazulite and scorzalite both dark blue and no definite correlation of colour with composition, and both sheets call the X-ray powder patterns nearly identical. The 1949 paper that described it says the Corrego Frio masses are rarely free from admixed souzalite. Separating it from lazulite takes an analysis or a refractive index; see lazulite vs scorzalite.
- Where. The sheet names the Corrego Frio pegmatite mine near Linópolis, Minas Gerais; the Victory and White Cap mines, South Dakota; the Palermo #1 and G.E. Smith mines, New Hampshire; the Champion mine, California; McIntyre Creek, Colorado; Buranga and Rusororo, Rwanda; Jebilet, Morocco; Hålsjöberget and Rånö, Sweden; and Hagendorf, Bavaria. It marks no type locality.
| Line | Worked from the sheet’s numbers | Printed on the sheet | Agrees? |
|---|---|---|---|
| Fe2+ | 0.658 | 0.66 | Yes |
| Mg | 0.337 | 0.34 | Yes |
| Zn (Mn 0.005 and Ca 0.001 not printed) | 0.007 | 0.01 | Yes |
| Fe3+ | 0.022 | 0.02 | Yes |
| Al | 1.943 | 1.93 | No, 0.013 high |
| Al + Fe3+ | 1.965 | Σ = 1.95 | No |
| OH | 2.088 | 2.08 | Close; rounds to 2.09 |
| Density, pure Fe2+Al2(PO4)2(OH)2 on the cell | 3.398 | — | — |
| Density, Corrego Frio composition (Fe0.66Mg0.34) | 3.289 | D(calc.) 3.32 | No |
| Density, Victory mine composition (Fe0.76Mg0.24) | 3.321 | D(calc.) 3.32; D(meas.) 3.33 (Pecora and Fahey measured 3.327) | Yes |
What is scorzalite? The iron end of the lazulite series
A ferrous aluminium phosphate. The September 2026 IMA list gives Fe2+Al2(PO4)2(OH)2, status G, 1949, Brazil; its first reference is Pecora and Fahey, American Mineralogist 34 (1949), titled The Corrego Frio pegmatite, Minas Gerais: scorzalite and souzalite, two new phosphate minerals. The Handbook of Mineralogy scorzalite sheet writes (Fe2+,Mg)Al2(PO4)2(OH)2, puts it in the lazulite group and says it forms a series with lazulite. The 1949 paper gives the Corrego Frio analysis as Fe:Mg 2:1 and proposes the names lazulite for the Mg-dominant and scorzalite for the Fe-dominant members, with adjective modifiers for intermediates: it says the Corrego Frio material might be termed magnesian scorzalite.
Its neighbours in the group. The scorzalite sheet cites Lindberg and Christ (1959) on the crystal structures of the isostructural minerals lazulite, scorzalite and barbosalite. The barbosalite sheet also puts that mineral in the lazulite group; its IMA formula, Fe2+Fe3+2(PO4)2(OH)2, has ferric iron where scorzalite has aluminium, and its sheet prints a dark blue streak and density 3.60 to 3.62. The magnesium end is on lazulite.
The Corrego Frio check, worked
Method. Each printed oxide weight of analysis (1), P2O5 42.90, TiO2 0.10, Al2O3 30.87, Fe2O3 0.54, FeO 14.74, MnO 0.11, ZnO 0.17, MgO 4.23, CaO 0.02, H2O 5.86, total 99.54, is turned into moles of each element on standard atomic weights and scaled so that phosphorus is the printed 1.94. Iron comes out 0.658, magnesium 0.337, zinc 0.007, ferric iron 0.022: each rounds to the printed figure. Manganese 0.005 and calcium 0.001 are left out of the printed formula; with them the first site sums to 1.008, the printed 1.01.
Documented failure: the aluminium. Aluminium comes out 1.943, against the printed 1.93, so the second site sums to 1.965, not 1.95. The ratio does not depend on the scaling: the oxide weights give 1.002 aluminium per phosphorus, the printed formula 0.995. Hydroxyl works out at 2.088, which rounds to 2.09 against 2.08. The sheet does not say how its formula was normalised, and this page does not guess. The same analysis gives the iron share used on lazulite vs scorzalite.
Why is scorzalite’s density 3.32? The 3.32 check
The cell. The sheet prints a 7.15, b 7.31, c 7.25 Å, β 120°35′, Z = 2, a volume of 326.22 ų, 0.74% larger than lazulite’s. Two formula units of the pure end member in it give 3.398; Fe:Mg 1:1 gives 3.237; the sheet’s own Corrego Frio composition, Fe0.66Mg0.34, gives 3.289. The printed D(calc.) 3.32 needs Fe0.757Mg0.243.
The match. Pecora and Fahey’s Table 2 lists eight analysed samples. The most iron-rich is from the Victory mine, South Dakota, at Mg:Fe 24:76, with a measured specific gravity of 3.327. Fe0.76 on this cell gives 3.321. The sheet’s 3.32 calculated and 3.33 measured therefore fit the Victory sample, while the analysis printed on the sheet, Corrego Frio, is the same analysis as their sample 6, measured at 3.268. A 20.00 g piece reads 13.99 g in water at 3.33 and 13.88 g at 3.268; method on how to measure specific gravity at home.
Where is scorzalite found?
As the sheet prints it. From the Corrego Frio pegmatite mine, Divino das Laranjeiras, near Linópolis, Minas Gerais, Brazil. In the USA, at the Victory mine, four km northeast of Custer, Custer Co., and the White Cap mine, three km south of Keystone, Pennington Co., South Dakota; in the Palermo #1 mine, near North Groton, Grafton Co., and the G.E. Smith mine, Newport, New Hampshire; at the Champion mine, Mono Co., California; from McIntyre Creek, about four km west of Glendevey, Larimer Co., Colorado. In the Buranga and Rusororo pegmatites, Gatumba district, Rwanda. At Jebilet, Morocco. From Hålsjöberget, Värmland, and in the Norrö pegmatite, on Rånö Island, Sweden. At Hagendorf, Bavaria, Germany. The sheet adds that other localities are reported, but chemical analyses would be desirable. It marks no type locality; see what is a type locality.
What it grows with. The sheet calls it typically a secondary mineral in complex zoned granite pegmatites, which may occur in kyanite-rich quartzite, with souzalite, triphylite, wyllieite, trolleite, apatite, lacroixite, berlinite, tourmaline, muscovite, feldspar and quartz. The 1949 paper lists brazilianite in the Corrego Frio pegmatite too, and describes scorzalite there as dark blue and massive, the largest mass about 7 cm across. More phosphates are in the species index.
Is scorzalite the same as lazulite?
Same structure, different metal. Both sheets give the same space group, P21/c, the same cleavages, {110} and {101}, and X-ray patterns they call nearly identical. Scorzalite has ferrous iron where lazulite has magnesium, and the name follows the ratio. The scorzalite sheet’s indices start where lazulite’s stop: α 1.626, β 1.654, γ 1.663 are the top of one range and the bottom of the other. Hardness is 6 against 5.5 to 6.
In practice. Pecora and Fahey call the gem name berkeyite applicable to gem scorzalite as well as gem lazulite. Whether a given blue phosphate is one or the other is set out on lazulite vs scorzalite; the lapis lazuli confusion, which affects both, is on is lazulite the same as lapis lazuli. We hold no catalogue and nothing here is offered for sale; the wanted list is the only commercial route.