Phosphophyllite
Phosphophyllite, Zn2Fe2+(PO4)2(H2O)4: sea-green monoclinic zinc phosphate, hardness 3 to 3.5, perfect {100} cleavage, density 3.08 to 3.13, Potosí, Hagendorf.
Phosphophyllite is a zinc iron phosphate, Zn2Fe2+(PO4)2(H2O)4 on the IMA list (G, 1920): monoclinic, sea-green to colourless crystals to 13 cm, hardness 3 to 3.5, density 3.08 to 3.13. The Handbook calls it brittle, with a perfect {100} cleavage and two distinct ones, so it is fragile. The name is phosphate plus the Greek for cleavage.
In short
- Fragile, on the record. The Handbook of Mineralogy sheet gives hardness 3 to 3.5, tenacity brittle, and cleavage perfect on {100} and distinct on {010} and {-102}: three cleavage directions. The International Gem Society calls it quite fragile and difficult to cut. How cleavage differs from fracture is on cleavage or fracture: how to tell.
- The manganese check. The September 2026 IMA-CNMNC Master List writes Fe2+ in the middle of the formula; the Handbook writes (Fe2+,Mn2+). Worked in atoms from the sheet’s analyses, manganese is 29.1% of the iron plus manganese at Hagendorf, Germany, and 0.9% at Potosí, Bolivia. The IMA row with the same atoms but manganese for iron is nizamoffite, Mn2+Zn2(PO4)2(H2O)4, IMA 2012-076.
- Is it a gem? The Handbook says nothing about cutting. The International Gem Society says only Bolivian phosphophyllite has been cut, and most faceted stones are 1 to 10 carats, cut from fragments and broken crystals. It names aquamarine as the popular gem of similar colour; the beryl sheet, which this site’s aquamarine pages work from, gives hardness 7.5 to 8 against 3 to 3.5.
- Where. The Distribution field names 11 places: Hagendorf, Bavaria; Přibyslavice, Czech Republic; the Norrö pegmatite, Rånö, Sweden; extraordinary crystals in the Unificada mine, Cerro Rico, and the Siglo XX mine, Llallagua, Potosí, and the Morococala mine, Bolivia; the Palermo #1 mine, New Hampshire; Red Hill, Rumford and Newry, Maine; Reaphook Hill, South Australia; and Kabwe (Broken Hill), Zambia.
- Documented disagreement: the lamp. A ligature-aware read of the Handbook sheet finds no fluorescence line, while the same script finds the lines on the hemimorphite and willemite sheets, its positive controls. The International Gem Society panel says it fluoresces violet in SW. Both are given here, attributed.
| Formula or analysis | Source | ZnO wt% | FeO wt% | MnO wt% | P2O5 wt% | H2O wt% | Fe, Mn per 2 P | Iron share of Fe + Mn |
|---|---|---|---|---|---|---|---|---|
| Phosphophyllite, Zn2Fe2+(PO4)2(H2O)4 | IMA list; worked | 36.28 | 16.01 | 0 | 31.64 | 16.06 | 1.00, 0 | 100% |
| Potosí, Bolivia (microprobe; H2O by Penfield) | Phosphophyllite sheet, analysis (2) | 34.59 | 16.18 | 0.14 | 32.29 | 15.99 | 0.99, 0.01 | 99.1% |
| Hagendorf, Germany | Phosphophyllite sheet, analysis (1) | 34.26 | 12.24 | 4.96 | 32.51 | 16.52 | 0.74, 0.31 | 70.9% |
| Nizamoffite, Mn2+Zn2(PO4)2(H2O)4 | IMA list (2012-076); worked | 36.35 | 0 | 15.84 | 31.71 | 16.10 | 0, 1.00 | 0% |
Is phosphophyllite fragile? Hardness and cleavage as printed
Yes, on every number the sheet prints. The Handbook of Mineralogy phosphophyllite sheet gives hardness 3 to 3.5 and tenacity brittle. Its cleavage line reads on {100}, perfect; on {010}, {-102}, distinct. The name itself is from phosphate and the Greek for cleavage. Twinning is common on {100}, the same plane as the perfect cleavage, as contact twins giving “fishtail” shapes and as penetration twins, and may be polysynthetic; it is rare on {-102}.
What the gem trade adds. The International Gem Society phosphophyllite article says phosphophyllite is quite fragile and difficult to cut, and lists low hardness, brittle tenacity, perfect cleavage and heat sensitivity as what makes cutting a large crystal risky. Its panel gives heat sensitivity as yes. This page offers no care or cleaning advice; the sheet prints none.
Against its zinc-phosphate relatives. hopeite is 3.5 with a perfect {010} cleavage; parahopeite 3.5 to 4 with a perfect {010}; scholzite 3 to 4 with only a fair {100}, which the sheet calls a parting. Softness alone does not separate them; the hopeite page sets them side by side.
What is phosphophyllite made of? The manganese check
Zinc, ferrous iron, phosphate and water. The September 2026 IMA list gives Zn2Fe2+(PO4)2(H2O)4, status G, 1920, country Germany, with the first reference in Zeitschrift für Krystallographie und Mineralogie 55 (1920), 523. The Handbook writes Zn2(Fe2+,Mn2+)(PO4)2·4H2O. On standard atomic weights the IMA formula is 29.15% zinc, 12.45% iron and 13.81% phosphorus by mass, or ZnO 36.28%, FeO 16.01%, P2O5 31.64% and H2O 16.06%.
The check. Divide each printed oxide by its formula weight and scale to two phosphorus atoms. The Potosí analysis gives Fe 0.99 and Mn 0.01: iron is 99.1% of the iron plus manganese. The Hagendorf analysis gives Fe 0.74 and Mn 0.31: iron 70.9%, manganese 29.1%. The International Gem Society reports the same contrast in words: the Bolivian material contains almost no manganese, the German material does. Both analyses carry more iron than manganese, which is the IMA formula’s arrangement.
The manganese formula has its own name. A script over the IMA list finds 14 rows whose formula holds zinc, phosphorus and iron or manganese, and nothing else but oxygen and hydrogen. One of them, nizamoffite, Mn2+Zn2(PO4)2(H2O)4, IMA 2012-076, USA, has phosphophyllite’s atoms with manganese in place of ferrous iron, written first in its formula. This page has not read the nizamoffite description and claims nothing about its structure.
Where the check stops. The same arithmetic gives the Hagendorf analysis only 1.84 zinc per two phosphorus, not 2. The sheet does not say where the extra manganese sits, and neither does this page. The check describes the iron-to-manganese ratio, nothing more.
Is phosphophyllite a real gem? What the sources say
A real mineral that has been cut, from one country. The Handbook sheet is silent on gem use. The International Gem Society says that Germany and Bolivia have produced gemmy material but that only Bolivian phosphophyllites have been cut, mostly as stones of 1 to 10 carats from crystal fragments and broken crystals. Its panel gives refractive index 1.595 to 1.621 and specific gravity 3.08 to 3.13, close to the sheet’s figures.
The colour look-alike. That source names aquamarine as the popular gem that shares its colours. Aquamarine is treated on this site’s beryl page and on is aquamarine a beryl; the beryl sheet gives hardness 7.5 to 8 and density 2.63 to 2.97, so a 20.00 g piece reads 12.40 to 13.27 g in water against phosphophyllite’s 13.51 to 13.61 g. It also names apatite and pargasite as overlapping in density and refractive index, and says both show pleochroism while phosphophyllite does not. The method is on how to measure specific gravity at home.
The lamp. A ligature-aware search of the Handbook sheet finds no luminescence line; the International Gem Society panel says it fluoresces violet in SW. The page gives both and does not choose. The general picture is on fluorescent minerals explained.
Where is phosphophyllite found? Potosí, Hagendorf and nine more
Eleven places on the sheet. The Distribution field reads, in order: Hagendorf, Bavaria, Germany; Přibyslavice, Czech Republic; the Norrö pegmatite on Rånö Island, Sweden; extraordinary crystals in the Unificada mine, Cerro Rico, and from the Siglo XX mine, Llallagua, Potosí; the Morococala mine, near Oruro, Bolivia; the Palermo #1 mine, near North Groton, New Hampshire; Red Hill, Rumford, and Newry, Oxford Co., Maine; Reaphook Hill, near Blinman, South Australia; and Kabwe (Broken Hill), Zambia. The sheet marks no type locality and gives type material as n.d.; the term is explained on what is a type locality.
How it forms. Typically a secondary mineral in zoned complex granite pegmatites, an alteration product of sphalerite and Fe–Mn phosphates, and in hydrothermal vein deposits. At Hagendorf its associates are triplite, triphylite, sphalerite, apatite, vivianite, rockbridgeite, strengite, phosphosiderite and fairfieldite.
Shared ground with hopeite. Hagendorf, the Palermo #1 mine and Kabwe are on both the phosphophyllite and the hopeite sheets. The hopeite page compares the green zinc phosphates found there. The rest of the reference section is at the species index. We hold no catalogue and nothing here is offered for sale; the wanted list is the only commercial route.