THE MINERAL CHILDRENITE

  • Chemistry: (Fe, Mn)AlPO4(OH)2 - H2O, Hydrated Iron Manganese Aluminum Phosphate Hydroxide.
  • Class: Phosphates
  • Uses: Only as mineral specimens.
  • Specimens

Childrenite is a classic secondary mineral that was first discovered in the mines of Devon, England especially the classic George and Charlotte Mine near Tavistock. It most likely forms from the alteration of primary granitic phosphates such as lithiophilite and triphylite when aluminum and water are available. Childrenite is also found in some ore veins.

Childrenite forms a solid solution series with the mineral eosphorite. Eosphorite's formula is (Mn, Fe)AlPO4(OH)2 - H2O and differs from childrenite only by being rich in manganese instead of iron. The structures of the two minerals are the same and therefore it would be expected that their differences in physical properties between the two would be related to the iron/manganese percentage. Eosphorite is less dense and is generally pinkish to rose-red in color whereas childrenite's colors tends towards various shades of brown. In terms of crystal habits the two also differ. Eosphorite forms prismatic, slender crystals and rosettes. Childrenite forms tabular or bladed individuals or lamellar aggregates. It has been said that the two different habits belie their solid solution relationship.

PHYSICAL CHARACTERISTICS:

  • Colors include dark yellow, yellow-brown and brown.
  • Luster is vitreous.
  • Transparency: Specimens are transparent to translucent.
  • Crystal System is orthorhombic; 2/m 2/m 2/m
  • Crystal Habits include equidimensional tabular, bladed or platy crystals. Aggregates include lamellar, parallel growth and fibrous habits.
  • Cleavage is good in two directions at right angles.
  • Fracture is conchoidal.
  • Hardness is 4.5 - 5.
  • Specific Gravity is approximately 3.2 (slightly above average).
  • Streak is white.
  • Associated Minerals include quartz, feldspars, lithiophilite, chlorite, pyrite, hureaulite and triphylite.
  • Notable Occurrences include the classic George and Charlotte Mine near Tavistock, Devon and some mines in Cornwall, England; Custer, South Dakota, USA and Minas Gerais, Brazil.
  • Best Field Indicators are crystal habit, color, associations, localities and density.
CHILDRENITE specimens:
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CHILDRENITE specimen chi-1
$ 120.00
Dims: 1.0 x 0.7 x 0.7" (2.6 x 1.8 x 1.7 cm)
Wt: 12 g w/ specimen box
Linopolis, Minas Gerais, Brazil
A cluster of intersecting Childrenite blades makes up this thumbnail specimen. These blades reach lengths of nearly 0.6" (1.5 cm) and are in good condition, showing surprisingly light breakage for their size and thinness. These crystals have good orthorhombic form and show a diamond-shaped cross-section. Their color is a dull pale brown and their luster is dull and pearly, and all are dimly transparent at best. The cluster is not attached to any base rock, and is hot-glued into a plastic thumbnail box.
no photo
chi-1 ($120.00)
Linopolis, Minas Gerais, Brazil
CHILDRENITE specimen chi-2
$ 36.00
Dims: 2.2 x 1.4 x 1.0" (5.7 x 3.6 x 2.5 cm)
Wt: 1.8 oz. (52 g)
Crinnis, Cliff, England
A few thin crusts cover most of the surface of the gray base rock of this hand specimen. A few of these crusts are made up of thousands of tiny crystals that do not exceed 1 mm in length or diameter. These crystals have the standard brown color and vitreous luster of Childrenite, and though they are too small to study without magnification, they appear to have good orthorhombic prismatic form and are even dimly transparent! The gray host rock on which they lay is definitely metamorphic in nature and appears to be some form of finely-grained schist, or possibly a slate.
no photo
chi-2 ($ 36.00)
Crinnis, Cliff, England
 

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