Crandallite
Current inventory:  0 gems
 

  
Crandallite was named in 1917 by Gerald F. Loughlin and Waldemar T. Schaller in honor of Milan Lucian Crandall, Jr. (1880 - 1959), mining engineer, Knight Mining Company, Provo, Utah, USA.

Discovered in 1917; IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

CaAl₃(PO₄)₂(OH)₅ · (H₂O)

Hydrated Calcium Aluminum Phosphate Hydroxide

Molecular Weight:

414.02 gm

Composition:

Calcium

9.68 %

Ca

13.54 %

CaO

Aluminum

19.55 %

Al

36.94 %

Al₂O₃

Phosphorus

14.96 %

P

34.28 %

P₂O₅

Hydrogen

1.70 %

H

15.23 %

H₂O

Oxygen

54.10 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Phosphates

Strunz 8th Ed. ID:

7/B.36-10

Nickel-Strunz 10th Ed. ID:

8.BL.10

8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H₂O
L : With medium-sized and large cations, (OH, etc.):RO₄ = 3:1

Related to:

Alunite Supergroup. Plumbogummite Group. Crandallite-Goyazite Series. The calcium analogue of Plumbogummite. The phosphate analogue of Arsenocrandallite.

Members of Group:

Plumbogummite Group: Benauite, Crandallite, Eylettersite, Florencite-(Ce), Florencite-(La), Florencite-(Nd), Florencite-(Sm), Galloplumbogummite, Gorceixite, Goyazite, Kintoreite, Kintoreite-2c, Plumbogummite, Springcreekite, Waylandite, Zaïrite 

Varieties:

Strontian Crandallite

Synonyms:

Calcio-wavellite, Lehiite, Lime-wavellite, Pseudowavellite

Crystal Data

Crystallography:

Trigonal - Hexagonal Scalenohedral

Crystal Habit:

As trigonal prismatic crystals, terminated by {0001}, or as pseudocubic rhombohedra, to 1 mm; as rosettes of fibers or spherules and crusts with radial fibrous structure; commonly as colloform to pulverulent crusts, nodular, massive. 

Twinning:

None

Physical Properties

Cleavage:

Perfect on {0001}

Fracture:

Irregular/Uneven

Tenacity:

Brittle

Moh's Hardness:

5.0

Density:

2.78 - 3.04 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Optical Properties

Color:

Yellow, white, gray; colorless in thin section. Theoretically white; iron may make the mineral yellow to brown; also frequently stained when fine-grained.

Transparency:

Translucent, Opaque

Luster:

Vitreous, dull to chalky when massive

Refractive Index:

1.613 - 1.632  Uniaxial ( + )

Birefringence:

0.009 - 0.011

Dispersion:

n/a

Pleochroism:

None

Occurances

Geological Setting:

In weathered phosphatic aluminous sedimentary rocks and carbonatites. In phosphate-rich nodules; from complex granite pegmatites; in amphibolite-grade metaquartzites. An authigenic mineral in anoxic marine sediments or in clay-rich sediment beneath a tropical swamp.

Common Associations:

Albite, Brazilianite, Fluellite, Fluorapatite, Hydroxylherderite, Limonite, Magnesite, Microcline, Montebrasite, Quartz, Senegalite, Siderite, Topaz, Variscite, Wardite, Wavellite

Common Impurities:

Sr, Ba, Fe

Type Locality:

Brooklyn Mine, Silver City, Tintic District, East Tintic Mts, Juab Co., Utah, USA

Year Discovered:

1917

View mineral photos:

Crandallite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Crandallite is an unusual hydrated phosphate mineral that is often associated with Variscite and Wardite at the type locality at the Little Green Monster Variscite Mine, Clay Canyon, Fairfield, Oquirrh Mountains, Utah County, Utah, USA. It is usually found in massive form and translucent to opaque white, gray or yellowish to brown if stained by iron.

Crandallite was named in 1917 by Gerald F. Loughlin and Waldemar T. Schaller in honor of Milan Lucian Crandall, Jr. (1880 - 1959), mining engineer, Knight Mining Company, Provo, Utah, USA.

Locations for Crandallite: In the USA, in Utah, from the Brooklyn mine, near Silver City, Tintic district, Juab County, at the Little Green Monster mine, Clay Canyon, about nine km west of Fairfield, and from Amatrice Hill, about 40 km northwest of Fairfield, Utah County; in the Palermo #1 and Fletcher mines, near North Groton, Grafton County, New Hampshire; from near Gore, Frederick County, Virginia; on Dug Hill, near Avant, Garland County, Arkansas; in several rock formations in central and northern Florida; from the Everly and Hugo mines, Pennington County, and in the Tip Top mine, 8.5 km southwest of Custer, Custer County, South Dakota. In the Alto Benedito pegmatite, 15 km west of Picuí, Paraíba, Brazil. At Blaton, Belgium. From Ronneburg, Thuringia, Germany. In Wheal Jane, Kea, Cornwall, England. At Fort Lismeenagh, Shenagolden, County Limerick, Ireland. From the Kovdor massif, Kola Peninsula, Russia. In Australia, in the Iron Monarch quarry, Iron Knob; the Moculta phosphate quarry, northeast of Angaston; and at the Mt. Weld carbonatite, 35 km south of Laverton, South Australia. In the Buranga pegmatite, near Gatumba, Rwanda.
 

  
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