Ca9 (Mg, Fe2+ )(PO4 )6 (PO3 OH)

Whitlockite

c 2001-2005 Mineral Data Publishing, version 1

Crystal Data: Hexagonal. Point Group: 3m. Typically as rhombohedral crystals, {0112},
rarely flat tabular {0001}, with {1120}, {1014}, several other smaller forms, to 2 cm. May formcave pearls; as anhedral grains and microcrystalline crusts.
Physical Properties: Fracture: Uneven to subconchoidal. Hardness = 5D(calc.) = 3.102 Piezoelectric and pyroelectric.

D(meas.) = 3.12

Optical Properties: Transparent to translucent. Color: Colorless, white, gray, yellowish;
colorless in transmitted light. Luster: Vitreous to subresinous.
Optical Class: Uniaxial (–). ω = 1.629  = 1.626
Cell Data:

Space Group: R3c. a = 10.330(2)c = 37.103(5)Z=3

X-ray Powder Pattern: North Groton, New Hampshire, USA.
2.88 (10), 3.21 (9), 2.60 (9), 5.24 (8), 3.47 (7), 1.72 (7), 1.93 (6)Chemistry:
P2 O5
Fe2 O3FeO
MgO
CaO

(1)
45.68
1.73
1.91
2.53
46.90

(2)
45.8
0.2
3.7
46.1

(1)
Na2 OFClH2 Oinsol.

(2)
3.3

0.06
trace0.48
0.51

Total 99.80
99.1(1) Palermo #1 mine, New Hampshire, USA; corresponds to Ca8.97 (Mg0.67 Fe0.52 )Σ=1.19(PO4 )6 (PO3 OH). (2) Dayton meteorite; by electron microprobe, corresponds to(Ca7.65 Na0.90 )Σ=8.55 (Mg0.87 Fe0.03 )Σ=0.90 (PO4 )6 (PO3 OH).
Occurrence: An uncommon secondary mineral in complex zoned granite pegmatites; inphosphate rock deposits; may be formed in caves from leached guano; in chondrite meteorites.
Association: Ludlamite, fairfieldite, triphylite, siderite, apatite, quartz (pegmatites);hydroxylapatite (caves and islands); stanfieldite, farringtonite, brianite (meteorites).
Distribution: In the USA, from the Palermo #1 mine, near North Groton, Grafton Co., New
Hampshire, as large crystals; in the Bell pit and Dunton quarry, Newry, Oxford Co., Maine;at the Tip Top and Bull Moose mines, near Custer, Custer Co., South Dakota. In the Tanco
pegmatite, Bernic Lake, Manitoba, Canada. On Table Mountain, Curaçao, and on Sombrero
Island, West Indies. From Enderbury Island, Phoenix Islands, Kiribati. On the Los Monges keys,Gulf of Venezuela. In Isla Mona Cave, Puerto Rico. At Cueva Atabex, Siboney, Cuba. Fromthe Ødegården apatite mines, Bamble, Norway. In the Drachenhöhle, Hungary. From a caveat Sebdou, Oran, Algeria. At the Niah Great Cave, Sarawak, Malaysia. In the Dayton finest
octahedrite meteorite.
Name: To honor Herbert Percy Whitlock (1868–1948), American mineralogist, Curator,
American Museum of Natural History, New York City, New York, USA.
Type Material: Harvard University, Cambridge, Massachusetts, 95030; National Museum ofNatural History, Washington, D.C., USA, 146196.
References: (1) Palache, C., H. Berman, and C. Frondel (1951) Dana’s system of mineralogy,(7th edition), v. II, 684–686. (2) Calvo, C. and R. Gopal (1975) The crystal structure ofwhitlockite from the Palermo quarry. Amer. Mineral., 60, 120–133. (3) Moore, P.B. and J.
Shen (1983) Cerite, RE9 (Fe3+ , Mg)(SiO4 )6 (SiO3 OH)(OH)3 : its crystal structure and relation towhitlockite. Amer. Mineral., 68, 996–1003. (4) Dowty, E. (1977) Phosphate in Angra dos Reis:structure and composition of the Ca3 (PO4 )2 minerals. Earth and Planetary Science Letters, 35,347–351. (5) Fuchs, L.H., E. Olsen, and E.P. Henderson (1967) On the occurrence of brianite andpanethite, two new phosphate minerals from the Dayton meteorite. Geochim. Cosmochim. Acta,31, 1711–1719. (6) Frondel, C. (1943) Mineralogy of the calcium phosphates in insular phosphaterock. Amer. Mineral., 28, 215–232.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted inany form or by any means, electronic, mechanical, photocopying, recording, or otherwise without the prior writtenpermission of Mineral Data Publishing.