Vesicular Basalt Value Guide

Vesicular Basalt is a distinctive extrusive igneous rock prized by collectors for its unique 'honeycomb' texture formed by trapped gas bubbles during rapid cooling. While basalt is found globally from the Giant's Causeway to lunar surfaces, vesicular specimens offer a tangible look at the volatile cooling process of volcanic lava.

What affects the value of Vesicular Basalt?

• Specimen size and the uniformity of the vesicular distribution across the rock.
• The presence of secondary mineral infillings, such as quartz or calcite, within the vesicles.
• Overall structural integrity and lack of significant weathering or crumbling.
• Provenance or specific geological origin, especially if linked to famous volcanic formations.

How to Identify Vesicular Basalt?

• Look for a dark, fine-grained matrix ranging from charcoal grey to deep black.
• Identify the presence of numerous small cavities or 'vesicles' scattered throughout the rock surface.
• Check for a heavy, dense feel despite the porous appearance, characteristic of its basaltic composition.
• Examine the texture for volcanic glass fragments which may be present within the fine-grained structure.

History of Vesicular Basalt

Basalt is a common extrusive igneous rock formed from the rapid cooling of basaltic lava exposed at or very near the surface of a planet or moon. It has been used by humans for construction, tools, and even road building throughout history, with notable examples like the Giant's Causeway in Northern Ireland.