Extrusive Igneous Rock Appraisal

Scoria (Lava Rock)

The item is a specimen of scoria, commonly known as lava rock, characterized by its dark, vesicular texture. Its overall shape is irregular and somewhat elongated, measuring approximately 6-8 inches in its longest dimension, resting on a gray, carpeted surface. The primary color is a dark gray to black, with variations in shade due to surface texture and minor accumulations of lighter-colored dust or sediment, particularly within the crevices. The rock exhibits high porosity, with numerous visible vesicles (gas bubbles) ranging in size from pinpricks to several millimeters across, which are typical for extrusive igneous rocks formed during volcanic eruptions. These vesicles give the rock a rough, spongy, and lightweight appearance. There are no clear distinguishing marks such as maker's marks, signatures, or stamps, as this is a natural geological specimen. No apparent repairs or significant damage are visible, though the naturally friable nature of scoria means small fragments could detach over time. The estimated age is geological, likely ranging from decades to millions of years, depending on the volcanic activity that formed it. Its unique aspect is its natural formation process, making each piece distinct. The material is volcanic rock, specifically scoria, indicating a rapid cooling process with trapped gases. The craftsmanship lies solely in its natural formation, providing an example of Earth's geological processes. The absence of polished surfaces or deliberate carving further confirms its natural state.