Formula: Mn2+Fe3+2(PO4)2(OH)2.6H2O
Hydrated phosphate containing hydroxyl
Specific gravity: 2.52
Hardness: 4
Streak: White
Colour: Straw-yellow to light brownish yellow


Strunzite is a secondary mineral, typically altered from triphylite, that occurs as a near-surface weathering product in pegmatites that contain triphylite, and also as films in weathered outcrops of phosphate rock (AM 43.793).
Associated minerals include laueite, beraunite, bermanite, diadochite, goethite, hureaulite, jahnsite, leucophosphite, ludlamite, mitridatite, phosphosiderite, pseudolaueite, quartz, rockbridgeite, siderite, stewartite, strengite, triphylite, vivianite and whitmoreite (HOM, Mindat).


At the type locality, the Hagendorf South Pegmatite, Waidhaus, Neustadt an der Waldnaab, Upper Palatinate, Bavaria, Germany, strunzite occurs as a late-stage alteration of primary phosphates, particularly triphylite (Mindat).

At the Emmons pegmatite, Greenwood, Oxford county, Maine, USA, strunzite crystals to one cm are common in parts of lithiophilite pods that have some iron content. Associated minerals include laueite, mitridatite and stewartite. The Emmons pegmatite is an example of a highly evolved boron-lithium-cesium-tantalum enriched pegmatite (R&M 94.6.516).

At the Chickering Mine, Walpole, Cheshire County, New Hampshire, USA, strunzite is a common late-stage product of hydrothermally altered triphylite. It is associated with almost all of the secondary phosphates in both altered triphylite and montebrasite assemblages (R&M 90.5.421).

Back to Minerals