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Childrenite
Current inventory:  1 gem
 

Chemistry:  Fe²⁺Al(PO₄)(OH)₂ • H₂O

Discovered in 1823;   IMA status: Valid (pre-IMA; Grandfathered).
Childrenite was named in honor of John George Children (1777 - 1852), an English chemist and mineralogist.

Classification

Mineral Classification:

Phosphates

Strunz 8th Ed. ID:

7/D.14-10

7 : Phosphates, Arsenates, Vanadates
D : Water-bearing phosphates with unfamiliar anions, mostly cations of small size: Be, Li
14 : Childrenite - Ernstite series

Crystal Data

Crystallography:

Orthorhombic - Pyramidal

Crystal Habit:

As equant to pyramidal crystals, may be short prismatic along [001], thick tabular on [010], or platy on [100], commonly doubly terminated, to 2 cm; in radiating groups and fibrous crusts; massive.

Twinning:

May show twinning on [100] and [001], observed optically, to give pseudo-orthorhombic symmetry; may be due to oxidation.

Physical Properties

Cleavage:

[100] Imperfect, Poor

Fracture:

Conchoidal to Uneven

Tenacity:

Brittle

Moh's Hardness:

4.5 - 5.0

Density:

3.18 - 3.25 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Optical Properties

Color:

White, Yellowish brown, Brownish black

Transparency:

Transparent to Translucent

Luster:

Vitreous to Resinous

Refractive Index:

1.649 - 1.691  Biaxial ( - )

Birefringence:

0.0270 - 0.0420

Dispersion:

Strong; r > v

Pleochroism:

X = yellow; Y = pink; Z = pale pink to colorless.

Occurances

Geological Setting:

In some complex granite pegmatites, typically a low-temperature hydrothermal alteration product of primary phosphate minerals.

Type Locality:

Tavistock District, Devon, England, UK

Year Discovered:

1832

View mineral photos:

Childrenite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Childrenite forms a series with Eosphorite, Childrenite being at the Fe end of the series and Eosphorite being at the Mn end of the series.  Both are rare gems, although Childrenite is much rarer than Eosphorite.  Childrenite is found as brown, yellowish brown and golden yellow crystals.  Facetable crystals from Minas Gerais, Brazil are usually brown. Crystals from other locations such as Cornwall, England; Greifenstein, Germany and Custer, South Dakota, USA are not facet grade. (photograph above courtesy of Jay Medici, gem also faceted by Jay Medici)
 

  
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