pitchstone

9.9

A dark, glass-like volcanic rock similar to obsidian

noun
/ˈpɪtʃˌstoʊn/

Specialized

: piedra de brea

Many pitchstones were scattered across the landscape.

Examples

Unlike obsidian, pitchstone often contains small crystals and water.
Jewelry made from polished pitchstone can have a striking appearance.
The geologist collected a sample of pitchstone from the old volcanic flow.
The pitchstone was found near the volcano.
The geological survey revealed that pitchstone is found in various locations across volcanic regions.
During our hike, we discovered a splendid piece of pitchstone glimmering in the sunlight.
The museum displayed a collection of rocks, including a striking sample of pitchstone related to obsidian.

Synonyms

obsidian

vspitchstone

7 7.9

A hard dark rock made when lava cools quickly and becomes like glass with a smooth shiny surface

focuses on acidic composition and relation rather than the rapid cooling formation

Surface Forms

pitchstone singular

pitchstones plural

Morphology

pitchstone = pitch + stone (transparent) = pitch + stone

Formed directly from 'pitch' + 'stone' meaning a stone resembling pitch; the compound meaning is directly inferable from its parts.

Etymology

Pitchstone is made of pitch and stone, and pitch means 'dark, sticky tar', so the name imagines a rock that looks like a lump of shiny tar. That's why pitchstone refers to a dark, glassy volcanic rock similar in look to obsidian.