Open-Base Amethyst Cathedral Geode – Brazil – 4.25 lbs

A substantial Open-Base Amethyst Cathedral Geode from Brazil, featuring a tall natural cavity lined with sparkling purple quartz crystals. Its broad arched opening, rugged natural exterior, and freestanding cathedral form create an impressive display from both the front and angled viewing positions.

The primary cavity contains dense amethyst crystallization extending across the interior walls. Individual points range from compact sparkling crystals to larger projecting terminations, producing considerable depth and reflective movement under direct lighting. The coloration varies naturally from pale lavender to richer purple, with subtle differences in saturation visible throughout the formation.

A lighter quartz-rich border surrounds the crystallized interior and contrasts against the darker natural host rock. The preserved exterior displays the rugged texture of the original geode, allowing the specimen to retain its geological character while maintaining a strong upright silhouette.

Unlike a fully enclosed cathedral, this specimen has an open base that reveals additional internal structure beneath the primary display cavity. This creates an especially interesting architectural presentation and allows the viewer to examine more of the geode’s natural formation.

Measuring approximately 7 × 5 × 6 inches and weighing 4.25 pounds, this is a substantial cabinet-sized amethyst specimen. Its balanced freestanding form, extensive crystal coverage, open-base construction, and classic Brazilian provenance make it an excellent centerpiece for a mineral collection, shelf, office, or natural-history display.

Specifications

Mineral: Amethyst Quartz

Formation: Open-base cathedral geode

Locality: Brazil

Weight: 4.25 lbs (approximately 1.93 kg)

Dimensions: Approximately 7 × 5 × 6 inches

Color: Pale lavender, purple, colorless-to-white quartz, gray, brown, and natural earthy matrix tones

Crystal Habit: Numerous terminated quartz crystals lining an open geode cavity

Interior: Deep cathedral-style cavity with extensive amethyst crystallization

Base: Naturally open formation with visible internal structure

Exterior: Rugged natural host rock and quartz-rich geode shell

Luster: Vitreous to glass-like across the crystal faces

Transparency: Transparent to translucent crystal points with opaque host matrix

Crystal System: Trigonal

Chemical Formula: SiO₂

Mohs Hardness: Approximately 7

Display: Naturally freestanding upright cathedral formation

Condition: Natural mineral specimen with inherent contacts, incomplete crystals, matrix fractures, edge irregularities, inclusions, color variation, and preparation marks associated with extraction and base stabilization

Exact specimen shown

About Brazilian Amethyst

Amethyst is the purple variety of quartz. Its coloration develops from trace iron within the crystal structure combined with natural geological irradiation. Differences in chemistry, crystal growth, and exposure can create variations ranging from delicate lavender to saturated violet within the same formation.

Brazil is one of the world’s most important sources of amethyst geodes and cathedral formations. These specimens developed inside cavities in ancient volcanic rock. Over long geological periods, silica-rich fluids entered the openings and deposited layers of chalcedony and quartz, eventually producing the inward-pointing amethyst crystals visible today.

The term “cathedral” describes a tall geode section with an arched, chamber-like opening. It is a trade and collector description based on the specimen’s appearance rather than a separate mineral variety.

Prolonged exposure to strong direct sunlight may gradually fade amethyst. Display the specimen away from intense window light and clean it carefully with a soft dry brush or gentle air blower.

Collector Notes

This specimen features:

• Natural Brazilian amethyst
• Substantial 4.25-pound cabinet size
• Approximately 7-inch presentation
• Upright cathedral-style silhouette
• Distinctive open-base formation
• Visible internal structure beneath the main cavity
• Extensive amethyst crystal coverage
• Numerous naturally terminated quartz points
• Pale lavender-to-purple coloration
• Strong sparkle under direct lighting
• Deep three-dimensional crystallized cavity
• Contrasting pale quartz border
• Rugged natural host-rock exterior
• Stable freestanding presentation
• Multiple attractive viewing angles
• One-of-a-kind natural mineral formation
• Exact specimen pictured

Perfect for collectors of Brazilian amethyst, cathedral geodes, open-base geodes, purple quartz, volcanic mineral formations, cabinet specimens, and statement-sized crystal displays.

Professionally packaged and shipped from Colorado.

You will receive the exact specimen shown.

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