Childrenite
Chemical formula: Fe<sup>2+</sup>AlPO<sub>4</sub>(OH)<sub>2</sub>·H<sub>2</sub>O
Childrenite is a rare iron and aluminum phosphate, forming characteristic, vitreous-lustered crystals ranging in color from yellow to brown, prized by collectors.
Properties
- Mohs hardness
- 5
- Luster
- Vitreous to resinous
- Streak
- White
- Density
- 3.06 - 3.2
- Cleavage
- Poor on {100} and {010}
- Fracture
- Uneven to subconchoidal
- Transparency
- Transparent to translucent
- Crystal system
- Orthorhombic
Diagnostic features
## Identification Childrenite can be identified by its characteristic tabular or pyramidal crystals, often forming fan-shaped aggregates. Its vitreous luster, yellowish-brown color, and hardness (around 5) are key features. It occurs in a specific geological environment – granitic pegmatites. ## Distinguishing from Similar Minerals Childrenite is most commonly confused with eosphorite, which is its manganese analog. Eosphorite usually has a lighter color (pink, orange, light brown) and slightly lower density. Definitive differentiation requires chemical analysis. It can also be confused with some tourmalines (schorl, dravite) or epidote, from which it is distinguished by lower hardness and different crystal forms. ## Crystal Forms Childrenite crystals are typically flattened, tabular, or in the form of steep, double pyramids. They often occur as radial or fan-shaped aggregates, as well as coatings and crusts on other minerals.
Geological environment
## Genesis Childrenite is a hydrothermal mineral, typical of complex granitic pegmatites. It forms in the late stages of pegmatite crystallization, in vugs and fissures, as a result of metasomatic alteration of earlier phosphates, such as triphylite or lithiophilite. ## Mineral Associations This mineral often co-occurs with other phosphates, such as eosphorite, wardite, strengite, rockbridgeite, as well as with quartz, albite, microcline, apatite, tourmaline, and muscovite. ## Localities The most important historical locality is Tavistock in Devon, England. Significant specimens also come from pegmatites in Minas Gerais, Brazil (especially from the Linópolis and Galileia regions), and from the United States (mines in the Black Hills region of South Dakota and in Maine). Occurrences have also been reported in Germany (Hagendorf), Sweden (Varuträsk), and Canada (Rapid Creek, Yukon).
Rarity
Rare
For collectors
## Quality Criteria The most prized specimens by collectors are those with sharp, well-formed crystals with distinct luster and an attractive, honey-yellow or brown color. Large, single crystals or aesthetically composed, radial aggregates on a quartz or rock matrix command the highest prices. Clarity and transparency, though rare, significantly increase the value of a specimen. ## Popular Localities Classic, though now rarely available, are specimens from Tavistock, England. Currently, the collector's market is dominated by material from Brazil, especially from the pegmatites in Minas Gerais, which yield the largest and best-formed crystals. Specimens from the Black Hills in the USA are also sought after, often for their interesting mineral associations.
Care and storage
## Cleaning Childrenite specimens should be cleaned very carefully, using a soft brush to remove dust. For heavier soiling, distilled water can be used, avoiding prolonged soaking. Ultrasonic cleaners should be avoided, as they can damage delicate aggregates. ## What to Avoid Childrenite is sensitive to strong acids and bases. It should be protected from sudden temperature changes and prolonged exposure to direct sunlight, which can affect its color. As a relatively brittle mineral, it is susceptible to mechanical damage. ## Storage Collectible specimens are best stored in individual, padded boxes or display cases, away from harder minerals that could scratch them. Stable humidity and temperature conditions are recommended for long-term preservation of specimens in pristine condition.