• A bunch of square tabular crystals with wispy white inclusions, and a coffee-brown coating on some parts of the crystals. The matrix is dark and bumpy and looks dusted with a light tan mineral. A cluster of scalenohedral calcite crystals is visible between the larger square crystals.
  • A mineral specimen with around twenty square tabular hydroxyapophyllite crystals, whiter color and translucent, with a brown coating on some. They are on a blobby dark matrix sprinkled with a light tan mineral.
  • Side-view of the piece, showing thick iron-bearing matrix.
  • Another angle of the mineral, with the side covered in crystals on the left so they are highlighted in profile against the white background. They are near-white and translucent. The piece is heavy with tabular crystals.
  • A row of tabular square crystals that are translucent white, and lined up along an edge of the specimen like a jawbone with crooked teeth.
  • Detail of a hydroxyapophyllite crystal with cubic pattern visible on its surface. Brown staining covers the beveled edges of the crystal.
  • The piece held up on the thumb and fingers for scale, showing the specimen in indirect sunlight. The luster is matte, and the crystals look quite white and translucent.
  • Scale image of the piece on its side on a measuring mat, measuring a bit over two inches long by an inch and a half wide.
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Hydroxyapophyllite

Hydroxyapophyllite

$55.00 USD
$55.00 USD
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Locale: N'Chwaning II Mine, South Africa

Approx dimensions: 2 x 1.5 x 1.25"

Approx weight: 145g

 

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.

This piece is covered with around two dozen hydroxyapophyllite crystals. The coffee-brown staining may be iron; the lighter brown mineral coating the specimen is lizardite, which often grows in small spots along the junctions of the hydroxyapophyllite crystal. Calcite has formed clusters of small scalenohedral crystals, and coats the specimen under the brown. Under UV light the calcite fluoresces from under the hydroxyapophyllite crystals, giving them a faint red glow—try it in a dark room.

The minerals are on a heavy dark matrix that 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.

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

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