Optical Calcite (Iceland Spar) with Phantom – Maharashtra, India – 1.49 lbs

A substantial Optical Calcite specimen from Maharashtra, India, displaying impressive transparency, prominent rhombohedral cleavage, and colorful internal rainbow reflections. Often called “Iceland Spar” in the mineral trade, transparent calcite is celebrated for its strong double-refraction effect, which can cause objects or printed lines viewed through clear portions of the crystal to appear doubled.

This specimen ranges from water-clear to softly translucent, with broad reflective surfaces and complex internal cleavage planes. Natural fractures, crystalline veils, and layered growth features interact with light to produce flashes of spectral color throughout the interior. When illuminated or viewed from different angles, these internal structures reveal shifting rainbows and luminous optical depth.

The blocky formation preserves calcite’s characteristic rhombohedral geometry, while stepped edges and overlapping cleavage surfaces create an architectural appearance. A softly clouded zone near the base contrasts beautifully with the clearer upper portions, emphasizing the specimen’s internal structure and substantial mass.

Measuring approximately 4 × 3 × 3.5 inches and weighing 1.49 pounds, this is an impressive cabinet-sized example with excellent display presence. Its combination of clarity, optical behavior, rainbow-producing internal features, and educational value makes it appealing to mineral collectors, science enthusiasts, and anyone fascinated by the interaction between crystals and light.

Specifications

Mineral: Calcite

Variety/Trade Name: Optical Calcite / Iceland Spar

Locality: Maharashtra, India

Weight: 1.49 lbs (approximately 676 grams)

Dimensions: Approximately 4 × 3 × 3.5 inches

Color: Colorless to milky white with internal rainbow reflections

Crystal Form: Blocky calcite with prominent rhombohedral cleavage

Luster: Vitreous to pearly along cleavage surfaces

Transparency: Transparent to translucent

Optical Property: Strong double refraction in sufficiently clear areas

Crystal System: Trigonal

Chemical Formula: CaCO₃

Condition: Natural mineral specimen with internal fractures, cleavage features, surface contacts, and edge irregularities

Display: Substantial collector and educational specimen

Exact specimen shown

About Optical Calcite

Calcite is a calcium carbonate mineral with the chemical formula CaCO₃. It crystallizes in the trigonal system and occurs in an extraordinary range of forms, including rhombohedrons, scalenohedrons, massive deposits, stalactites, and transparent cleavage fragments.

Highly transparent calcite is widely known as optical calcite or Iceland spar. The historic name “Iceland spar” originated with exceptionally clear material from Iceland but is now commonly used in the mineral trade for transparent calcite exhibiting strong optical properties, regardless of locality.

Calcite is strongly birefringent, meaning that light entering the mineral is divided into two rays traveling at different speeds and directions. This phenomenon produces the mineral’s famous double-refraction effect. When a sufficiently clear piece is placed over a line or small object, two separate images may be visible through the crystal.

Maharashtra lies within the Deccan Traps, an immense volcanic province renowned for producing calcite, apophyllite, stilbite, heulandite, chalcedony, and many other collectible cavity minerals. Mineral-rich fluids circulated through openings in the ancient basalt, depositing crystals during successive stages of low-temperature mineralization.

Collector Notes

This specimen features:

substantial optical calcite from Maharashtra, India
transparent to softly translucent crystalline areas
classic double-refraction potential through clearer sections
prominent rhombohedral cleavage geometry
broad reflective calcite surfaces
numerous internal cleavage planes and crystalline veils
vivid natural rainbow reflections
complex optical depth under direct lighting
contrasting clear and softly clouded zones
impressive cabinet-sized dimensions
excellent educational and scientific interest
material from India’s renowned Deccan Traps region
one-of-a-kind natural mineral specimen
exact specimen pictured

Perfect for collectors of optical calcite, Iceland spar, Indian minerals, Maharashtra specimens, transparent crystals, rainbow minerals, birefringent minerals, educational geology specimens, optical mineral displays, and substantial cabinet specimens.

Professionally packaged and shipped from Colorado.

You will receive the exact specimen shown.

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