• Detail of a translucent white hydroxyapophyllite crystal with an almost spray-like pattern of wispy inclusions out from the center. The surrounding matrix has a sandy texture coated in light lizardite
  • A mineral specimen with about a dozen square tabular crystals on a thin plate of dark matrix and coated with a light brown mineral.
  • The specimen in indirect sunlight, showing the bright white translucency of the hydroxyapophyllite crystals, some with coffee-brown iron staining on the surface.
  • Front view of the specimen, a flat bumpy piece of dark matrix with a dusting of light brown lizardite over it. At the center of the specimen is a pair of intersecting hydroxyapophyllite crystals
  • Angled view of the front of the specimen, showing the larger of the intersecting crystals is quite thick.
  • Detail of a pair of milky white semi-translucent hydroxyapophyllite crystals on the bumpy matrix textured like cauliflower.
  • Side-view of the specimen, showing the matrix is an extremely thin crust.
  • The back of the specimen, mostly covered with a fine light colored calcite druzy with the dark matrix peeking through.
  • Scale image of the piece on a measuring mat, measuring about two and a half inches long by nearly two inches wide.
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Hydroxyapophyllite

Hydroxyapophyllite

$45.00 USD
$45.00 USD
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Locale: N'Chwaning II Mine, South Africa

Approx dimensions: 2.5 x 1.75 x .25"

Approx weight: 25g

 

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 matrix on this specimen is very thin, and displays a well-formed pair of intersecting crystals at the center. The light matte 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 stacks of small scalenohedral crystals. The dark matrix is likely manganese-based; the N'Chwaning mines were established to extract the rich manganese ore in the area. Coffee-brown staining may be iron.

UV reactivity Calcite can cause the hydroxyapophyllite crystals growing over it to glow a weak red under 365 nm UV light—try it in a dark room with a strong flashlight. An unknown whitish mineral finely dusts areas of the specimen strongly fluoresces icy blue.

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

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