Quartz Crystal Geode — Matched Pair, Natural Split, Druzy Interior

Formed approximately 340 million years ago as a mud concretion in ancient sedimentary rock, this naturally split geode reveals a sparkling interior of white druzy quartz with larger blocky crystals at the center — the slow, pressurized work of silica-rich water moving through a hollow cavity over geologic time. The exterior is a standout: a multi-tone rind of russet, terracotta, and olive-green matrix with scattered white mineral inclusions, far more visually dynamic than the plain gray chalcedony exterior typical of common stock. In form and structure, this specimen is consistent with Keokuk-type geodes from the Iowa/Illinois/Missouri tri-state region — home to one of the world's most storied geode collecting traditions and the official state rock of Iowa since 1967.

Offered as the complete matched pair with the natural fracture line intact on both halves. Supplemental reference images show the nodule in its closed, pre-split state — an unusual documentation that gives bidders a full picture of the specimen from rough exterior to sparkling interior.

CONDITION Very Good. Both halves are intact with crystal interiors clean and undamaged throughout. Minor matrix chipping present along the natural split edge of one half; no crystal loss visible.

DIMENSIONS / SPECIFICATIONS

• Overall: 3.5" H × 4" W × 4.5" D
• Weight: 2 lbs
• Quantity: 2 halves (matched pair)
• Crystal Type: Quartz druzy lining; larger blocky crystals at center (likely calcite)
• Host Rock: Multi-color sedimentary matrix — russet, terracotta, olive-green
• Split Type: Natural fracture (uncut)
• Probable Type: Keokuk-style geode (morphology-based; provenance unconfirmed)
• Age: Approximately 340 million years (Mississippian period)

Campbell's Soup Can (4" H) Shown for Scale