Igneous Stone Laser Cleaning Materials
Technical parameters for laser cleaning of igneous stones including granite, basalt, andesite, diorite, rhyolite, and obsidian. Optimized for graffiti removal, biological growth elimination, and soot cleaning without surface erosion.
Hardness & Porosity Variation Management
Igneous rocks range from obsidian (5-6 Mohs) to granite (6-7 Mohs). Laser parameters must adjust for hardness: softer stones (andesite, basalt) require fluence below 1-2 J/cm² to avoid surface melting, while granite tolerates 2-5 J/cm² for heavy contamination.
Dark Stone Thermal Absorption
Dark-colored igneous stones (basalt, obsidian, dark granite) absorb 60-80% of laser energy vs 20-40% for light granite. Reduce fluence by 30-50% on dark stones to prevent thermal spalling or surface vitrification.
Biological Growth & Patina Removal
Lichen, moss, and algae penetrate 2-10 mm into porous igneous surfaces. Laser cleaning removes surface growth effectively but leaves deeper hyphae intact. For historic monuments, combination with biocide treatment achieves >95% total removal.
Historic Granite Monument Cleaning
Granite monuments develop black gypsum crusts from air pollution (SO2 + calcium minerals). Laser cleaning removes these 200-500 micron crusts without the 1-3 mm material loss typical of sandblasting, preserving carved lettering and fine details.