pitchstone

Thân thiện

A geologist examines a piece of pitchstone in the field.

Definition

1. Noun:
   • A type of volcanic glass: Pitchstone is a dark, usually black or dark green, natural glass formed by the rapid cooling of lava. It is similar to obsidian but has a dull, resinous or pitch-like luster, rather than a glassy shine, and often contains microscopic crystals.

Usage

• Pitchstone is a geological term used to describe a specific type of igneous rock. It is primarily used in academic, scientific, and geological contexts.
• Example:

Advanced Usage

• As a material: Historically, like obsidian, pitchstone could be fashioned into sharp tools or weapons by knapping due to its conchoidal fracture.
  • Example: Archaeologists found pitchstone artifacts at the site, indicating trade from volcanic regions.

Variants and Related Words

• Obsidian (noun): A closely related volcanic glass that is typically black and has a bright, glassy luster, unlike the dull luster of pitchstone.
• Tachylite (noun): A basic (low-silica) volcanic glass, which is darker and heavier than the acidic (high-silica) pitchstone.

Synonyms

• Volcanic glass: The general category to which pitchstone belongs.

Different Meanings

• The word "pitchstone" does not have other common meanings outside of its specific geological definition. It is a compound noun formed from "pitch" (referring to its tar-like appearance) and "stone".

Học thuật

Noun

1. dark acid granitic glass