pitchstone
Resinous ignite rock
Pitchstone is a volcanic glass with a waxy or resinous luster, resembling hardened pitch.
It forms when lava cools rapidly, trapping water within its glassy structure.
The rock appears in dark colors—black, green, or brown—and breaks with curved, shell-like fractures.
It resembles obsidian but contains more water.
Glassy igneous rock
- vitreousGlass-like in appearance
- lustrousSoftly bright, reflective
- resinousContaining plant sap
- conchoidalCurved fracture surface shape
translucent · waxy · sheen · fracture · luster · glossy · smooth · brittle
Pale volcanic igneous rock
- obsidianGlassy igneous rock
- graniteIgneous rock, quartz-rich
- andesiteIntermediate volcanic rock
- extrusiveExpelled and solidified outside
lava · magma · silica · feldspar · quartz · crystallization · mineralogy · petrology
Moving volcanic discharge
- eruptionViolent sudden release
- pyroclasticHot eruption debris
- calderaCollapsed volcanic summit basin
- tuffSolidified volcanic ash
pumice · scoria · geothermal · volcano · vent · dome · effusive · volcanic rock
obsidian
Glassy igneous rock
conchoidal · translucent · waxy · sheen · fracture · luster · glossy · smooth · brittle · amorphous
rhyolite
Pale volcanic igneous rock
extrusive · lava · magma · silica · feldspar · quartz · crystallization · mineralogy · petrology · groundmass
lava flow
Moving volcanic discharge
- eruptionViolent sudden release
- pyroclasticHot eruption debris
- calderaCollapsed volcanic summit basin
tuff · pumice · scoria · geothermal · volcano · vent · dome · effusive · volcanic rock · tephra
stone, stoneware, stonewall, stonework, stonemason, stoneless, stoneground, stonewashed, stonecutter