• Detail of a square hydroxyapophyllite crystal, semi-translucent milky white with a smaller square form on the surface, and darker brown iron staining.
  • Full view of the specimen, with six hydroxyapophyllite crystals visible, and lumpy almost ropy textured matrix
  • A mineral specimen with square tabular crystals on a lumpy dark matrix coated in a light brown mineral.
  • Angled view of the front of the specimen emphasizing the folds in the lumpy matrix, with dark matrix showing through the lighter brown mineral layer
  • Detail of a clean white hydroxyapophyllite crystal on the surface without any mineral overgrowth
  • Detail of a hydroxyapophyllite crystal with iron staining on the main square face, and a second overlay layer of light brown lizardite in small dots as if spray-painted on.
  • The back of the specimen, with a dark matrix showing through bumpy layer of tan mineral growth.
  • Scale image of the piece on a measuring mat, measuring almost two and a half inches long by an inch and a half wide.
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Hydroxyapophyllite

Hydroxyapophyllite

$40.00 USD
$40.00 USD
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Locale: N'Chwaning II Mine, South Africa

Approx dimensions: 2.25 x 1.5 x .75"

Approx weight: 47g

 

This specimen features hydroxyapophyllite crystals with lizardite and calcite on matrix. Properly called "hydroxyapophyllite-(K)," hydroxyapophyllite is a variety of apophyllite that is typically colorless. It more frequently grows cubic crystals, but these specimens from the renowned N'Chwaning Mines region form tabular square crystals similar to wulfenite, and can be colorless to semi-translucent white with inclusions.

The matte light brown mineral coating the specimen is lizardite, which often grows in small spots along the junctions of the hydroxyapophyllite crystal. Calcite druzy glitters through the lizardite and covers the back of the specimen. The calcite has also formed clusters of small scalenohedral crystals. The heavy dark matrix is likely manganese-based; the N'Chwaning mines were established to extract the rich manganese ore in the area. The coffee-brown staining may be iron.

UV reactivity Visible calcite fluoresces and phosphoresces faint red under 365 nm UV light. It can cause the hydroxyapophyllite crystals growing over it to glow a faint red—try it in a dark room with a strong flashlight.

** Brittle warning! Hydroxyapophyllite specimens are somewhat delicate and may shed pieces; limit handling.

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