Iceland Spar — Optical Calcite — Display Piece

$75.90
Chemical FormulaCaCO₃
Crystal SystemTrigonal
Mohs Hardness3
Specific Gravity2.71
LusterVitreous
TransparencyTransparent

Iceland spar — transparent, colorless calcite — famously shows double refraction: place a crystal over text and see two images. It was used in Viking navigation (the ‘sunstone’ of …

21 in stock

SKU: TC-MIN-0088
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Description

What looks like stone is, on closer inspection, frozen time. Iceland spar — transparent, colorless calcite — famously shows double refraction: place a crystal over text and see two images. It was used in Viking navigation (the ‘sunstone’ of sagas) and later in optical instruments before glass could be made pure enough. The Helgustaðir deposit in Iceland is the historical source.

This specimen originates from Helgustaðir, Iceland, one of the world’s most significant localities for this type of material. Collectors and scientists have drawn from this region for generations, and for good reason: the combination of geological conditions here produces specimens of exceptional quality and clarity.

Every specimen is unique. Photographs approximate the visual experience, but the real thing — its weight, its luster under a raking light, the way it catches the corner of your eye — can only be experienced directly.

Formation

This specimen formed through geological processes operating over timescales that dwarf human history. The specific combination of chemistry, temperature, pressure, and time at this locality produced material of exceptional quality that makes it a valued addition to any serious collection.

Locality

Iceland Spar — Optical Calcite — Display Piece from Helgustaðir, Iceland. This locality is known for producing specimens of exceptional quality.

Collector Notes

Best displayed where natural light can play across the surfaces at different times of day.