• The front of the piece of aragonite and calcite, a rectangular piece covered with calcite points coated in textured aragonite of a light tan color. There is a crack across the top crust.
  • Side angle of the front of the mineral, with a larger point in the foreground. The points re on a crust-like top with porous hollow between them and the matrix.
  • Side-view of the piece, showing it has a crust-like layer of the points on the matrix with some hollow between.
  • The front of the mineral, showing detail of a fracture line through the aragonite that has been repaired
  • Close view of the back of the mineral, which is irregularly formed almost like a white honeycomb with irregular yellow glassy mineral in between
  • Close up of the side of the piece showing the aragonite crust layer with hollow between it and the matrix
  • Close up of aragonite crust with an irregular shiny crystal stuck in it
  • Close up of bottom and edge of the mineral showing hollow under the aragonite crust
  • Detail of glue in a fracture line. The points nearby are textured as if composed of small blades.
  • Scale image of the mineral on a measuring mat, measuring about three and a half inches long and two inches wide.
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Aragonite and calcite (repaired)

Aragonite and calcite (repaired)

$18.00 USD
$22.00 USD $18.00 USD
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Locale: Sidi Ayed, Fès-Meknès Region, Morocco

Approx dimensions: 3.5 x 2 x 1.5"

Approx size: 285g

**Repaired specimen

 

Calcite and aragonite are polymorphs of one another, meaning that the same chemical composition (calcium carbonate) has crystallized into different crystal structures (trigonal and orthorhombic, respectively). Calcite and aragonite often grow together, and the two minerals are also frequent paramorphs of one another—a pseudomorph of the same chemical composition and retaining the original crystal shape but with different crystal structure, created through a change of conditions such as heat or pressure. There is understandably some confusion distinguishing what is calcite, versus aragonite, or a paramorph, or some hodgepodge of all of the above.

Which is all to say, this specimen falls somewhere in that ‘hodgepodge’ category. It appears aragonite formed over calcite points which then partially dissipated, leaving some hollow honeycomb-like structure between the points and matrix. Where points have broken, you can see they are hollow inside. On the back is a messy mix of semi-formed glossy yellow-tinted crystal and white honeycomb mineral.

Repaired: This specimen has been repaired, meaning it broke but someone recompiled and glued it back together. Part of the crust was dislodged but set back in place well, but with some glue visible from the repair. It typically is not disclosed when Moroccan minerals are recompiled and glued :( Read more about how to detect repairs.

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