• Detail of several translucent white hydroxyapophyllite crystals, with three of the square tabular crystals intersecting. They have a light cubic of crosshatch pattern visible in the inclusions or on the surface. There are brown spots of lizardite along the side faces, but the main square faces are. Below to the left is a cluster of stacked scalenohedral calcite crystals, mostly covered in the brown mineral.
  • A mineral specimen with several square tabular crystals on an irregularly-shaped matrix with dark cave-like pockets into the surface. It is coated in a matte brown mineral.
  • Another angle of the piece showing an unusual conical formation of matrix poking out the side. On the front is a cave-live hole.
  • The back of the specimen, with a raised wishbone-shape of exposed near-black matrix. Around it the surface is covered in off-white druzy speckled on the dark surface.
  • Detail showing several of the tabular crystals. The largest in the far right has an angled edge instead of two symmetric small faces on the edges.
  • Detail of a tabular crystal white with inclusions spreading out from the center with clarity at the edges. The surface is textured like cauliflower with the brown lizardite coating it. There is also a small tabular crystal about a quarter the size of the others in the top left.
  • Detail of several of the tabular crystals with the one at the center of the image tilted to reflect light. It has an unusual luster a bit like oil on water in places. Under it is a cluster of scalenohedral calcite crystals with brown lizardite largely covering them.
  • The piece held between thumb and finger for scale, in indirect sunlight. The luster is matte.
  • The back of the piece held between thumb and finger for scale, in indirect sunlight. The druzy is off-white and has some glitter. Red coloration is visible in the dark matrix.
  • Scale image of the piece on a measuring mat, measuring about two and a quarter inches long by over an inch and a half wide.
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Hydroxyapophyllite

Hydroxyapophyllite

$65.00 USD
$65.00 USD
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Locale: N'Chwaning II Mine, South Africa

Approx dimensions: 2.25 x 1.5 x 1"

Approx weight: 95g

 

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 brown mineral coating the specimen is lizardite, which often grows in small spots along the junctions of the hydroxyapophyllite crystal. It especially highlights structure of the hydroxyapophyllite crystals of this piece. The largest crystal (just shy of 1cm) has a different shape from the rest: instead of two symmetrical faces on the edges it has one very large face and one that barely exists.

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.

UV reactivity Visible calcite fluoresces and phosphoresces moderate 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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