Rainbow Optical Calcite – Maharashtra, India – 0.32 lbs

An extra-quality Rainbow Optical Calcite specimen from Maharashtra, India, featuring excellent transparency, strong internal optical effects, and vivid spectral flashes. Naturally self-standing, the specimen presents an architectural, crystal-like profile that displays beautifully without requiring the stand shown in the photographs.

The calcite ranges from nearly water-clear to softly translucent, with broad viewing windows revealing layered cleavage planes, internal veils, and reflective features throughout the specimen. When moved beneath direct light, selected internal fractures separate the light into flashes of blue, violet, green, yellow, orange, and red. These natural rainbow displays appear and disappear as the viewing angle changes, making the specimen especially engaging in person.

Its wedge-shaped form is defined by calcite’s characteristic rhombohedral cleavage. Large flat surfaces provide clear views into the interior, where overlapping planes and subtle internal structures create shifting reflections and optical depth. Calcite is also naturally birefringent, meaning that clear portions can split transmitted light and produce double images when viewed over text or fine patterns.

Measuring approximately 2.25 × 1 × 2.25 inches and weighing 0.32 pounds, this compact specimen combines excellent clarity, strong rainbow activity, educational optical properties, and convenient freestanding display. Its high transparency and colorful internal reflections distinguish it from more ordinary cloudy calcite pieces.

Specifications

Mineral: Calcite

Variety/Trade Description: Rainbow Optical Calcite — Extra Quality

Locality: Maharashtra, India

Weight: 0.32 lbs (approximately 145 grams)

Dimensions: Approximately 2.25 × 1 × 2.25 inches

Color: Colorless to icy white with multicolored internal rainbow reflections

Form: Natural cleavage specimen with a wedge-shaped, architectural profile

Luster: Vitreous to glass-like

Transparency: Transparent to translucent

Optical Property: Strong birefringence or double refraction through sufficiently clear areas

Rainbow Effect: Natural spectral flashes produced where light interacts with internal cleavage and fracture surfaces

Crystal System: Trigonal

Chemical Formula: CaCO₃

Mohs Hardness: Approximately 3

Display: Naturally self-standing; display stand shown is not included unless otherwise specified

Condition: Natural calcite specimen with inherent cleavage lines, internal fractures, contacts, surface textures, and edge irregularities

Exact specimen shown

About Optical Calcite

Calcite is a calcium carbonate mineral with the chemical formula CaCO₃. It crystallizes in the trigonal system and is well known for its perfect rhombohedral cleavage, which allows it to separate along three consistent directions that do not meet at right angles.

Exceptionally transparent calcite is often described as optical calcite because of its pronounced birefringence. Light entering the mineral is divided into two rays traveling at different speeds. When a clear piece is placed over text or a fine line, this effect can produce two visible images.

The rainbow colors are a separate optical phenomenon. Thin internal fractures and cleavage separations act as natural prisms or interference surfaces, dividing white light into spectral colors. The intensity and position of these rainbows change with the lighting and viewing angle.

Calcite is significantly softer than quartz and possesses perfect cleavage. It should be handled carefully, kept away from acids, and cleaned without soaking. A soft dry brush or gentle microfiber cloth is recommended.

Collector Notes

This specimen features:

• Extra-quality optical calcite
• Transparent to highly translucent viewing areas
• Vivid internal rainbow flashes
• Blue, violet, green, yellow, orange, and red spectral color
• Broad natural cleavage surfaces
• Strong internal depth and layered reflections
• Calcite’s characteristic double-refraction effect
• Distinctive wedge-shaped architectural form
• Naturally self-standing presentation
• Compact size with excellent visual impact
• Material from Maharashtra, India
• Both decorative and educational appeal
• One-of-a-kind natural mineral specimen
• Exact specimen pictured

Perfect for collectors of optical calcite, rainbow calcite, transparent minerals, birefringent crystals, natural optical phenomena, Indian minerals, educational specimens, and self-standing mineral displays.

Professionally packaged and shipped from Colorado.

You will receive the exact specimen shown.

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