Overview
This is a museum-quality example of a Handmade German Clambroth Marble, dating from the late 19th to early 20th century (circa 1860–1920). While white-based Clambroths are common, this specimen features a deep opaque black base, which is significantly rarer and more sought after by advanced collectors.

Item Details
• Type: Handmade Clambroth Swirl.
• Origin: Germany.
• Colors: High-contrast Opaque Black base with crisp, even White strands.
• Size: Approximately 21mm (13/16")—a desirable "Large Cabinet" or "Shooter" size. Measured with tape measure.
• Pontil: Features a classic single rough-snapped pontil at the pole, confirming its authentic handmade construction.
Condition Report
Grade: Near Mint (8.7 – 8.9)
• Luster: The marble retains a beautiful, high-gloss "wet" factory shine.
• Surface: Very clean overall with a few tiny "flea bites" (micro-pinpricks) and minor subsurface "moons" (small impact sparkles) visible upon close rotation under light.
• Structure: No deep chips, flat spots, or annealing cracks. The rough pontil is a factory-original "as-made" mark and is not considered damage.

Why Add This to Your Collection?
The combination of the large 13/16" size and the rare black colorway makes this a standout piece. The white strands are exceptionally well-spaced and converge perfectly at the poles, showcasing the high level of craftsmanship from the German glass houses of the era.