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Whitmoreite

Named for Robert William Whitmore, a mineral collector and owner of the Palermo No.1 mine in New Hampshire, USA where Whitmoreite finds its type locality. Whitemoreite can be found in several localities in Europe and the Unites States, including the Tip Top, Big Chief, and White Cap mines here in the Black Hills of South Dakota. Occurs as “a secondary mineral in complex zoned granite pegmatites” and can be a product of hydrothermally altered triphylite.
Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/whitmoreite.pdf
- Formula
- Fe2+Fe3+2(PO4)2(OH)2ยท4H2O
- Crystal System
- Monoclinic
- Crystal Habit
- Acicular, Radial, Aggregates
- Cleavage
- Good, None, None
- Luster
- Vitreous - Adamantine
- Color
- brown, greenish brown, light yellow brown, dark brown
- Class
- Monoclinic - Prismatic
- Hardness
- 3
- WebMineral
- View Whitmoreite
- Mindat
- View Whitmoreite
Whitmoreite from Big Chief mine, Pennington Co., South Dakota, United States

This is a superb specemin loaded with what Willad oberts coined "floating naval mines," which is how he described the crystals of this mineral. The crystals are acicular and root beer colored, protruding from a brown spheroidal center. These crystals reach maybe 0.75 to 1mm in size and are free-standing in vuggy Siderite matrix altered from Ludlamite in phosphate nodules.
Whitmoreite from Hagendorf-Süd, Oberpfälzer Wald, Bavaria, Germany

Hagendorf was a huge zoned granitic pegmatite which produced a million tons of feldspar. This specimen is just one of numerous secondary phosphates which were found at Hagendorf. This specimen contains abundant little sprays of Whitmoreite, a mineral once described by Willard Roberts as "floating naval bombs" - (balls with spikes) in reference to the crystals found at the Big Chief mine in South Dakota. This habit holds true for most occurences.
Whitmoreite from Gravel Hill mine, Perranzabuloe, Cornwall, England
Beautiful, superb sprays of rare Whitmoreite as single groups tp 0.75mm. This is the best Whitmoreite I have ever seen from any locality. Strunzite is shown in the last photo.