On offer is a substantial aqua-green glass specimen of approximately 10.5 inches (26.7 cm) in length × 7.5 inches (19.0 cm) wide × 4.5 inches (11.4 cm) thick, weighing approximately 21 lbs (9.4 kg). It was reportedly recovered some time ago from an old coal mine. While it has the appearance of a large size volcanic glass such as obsidian, closer examination suggests it may in fact be slag or industrial glass rather than natural obsidian.

True obsidian is a naturally occurring volcanic glass formed when felsic lava cools rapidly and typically occurs in restricted localities, often in black or very dark colours, and rarely in transparent or bright green hues. epigem.de+2Wikipedia+2 Many collectors and mineral-identification forums advise that aqua or bright green glass—especially found in coal-mine or industrial dump contexts—is more likely slag or manufactured glass rather than genuine volcanic obsidian. Reddit+1

This specimen displays sharp, irregular edges and a deep aqua-green hue which may reflect industrial glass origins rather than purely volcanic formation. As such, rather than presenting it definitively as volcanic obsidian, this description presents both possibilities and leaves open the correct identification. It remains a striking and substantial piece for display or geological interest.

KEY FEATURES
✅ Large aqua-green glass/rock specimen (~10.5″ x 7.5″ x 4.5″; ~9.4 kg)
✅ Reportedly recovered from a coal-mine environment
✅ Highly decorative display potential – when light passes through the material it shows vivid colour
✅ Possibly man-made slag or industrial glass rather than natural obsidian – due to vivid aqua colour and context
✅ Condition: Raw, unpolished edges; some sharper fragments—please handle with care

SHIPPING & INTERNATIONAL BUYERS
We ship worldwide using tracked, insured services. Shipping is calculated at checkout and this heavy item will be well-packed and boxed for safe transit.
Customs & Import Duties:
USA buyers: All customs duties are paid at checkout.
All other countries: Customs charges may apply upon delivery. Buyers are responsible for checking local import rules and fees before purchasing.