obsidian
UK[əbˈsɪd.i.ən]US[əbˈsɪd.i.ən]
n
A type of dark, hard, glass-like volcanic rock, often black or dark green, that breaks with a very sharp edge.
Etymology
The word 'obsidian' entered English in the early 17th century via Latin 'obsidianus lapis', meaning 'stone of Obsidius'. This name refers to a certain Obsidius (or Obsius), a Roman figure mentioned by Pliny the Elder, who was said to have discovered a similar stone in Ethiopia. The Latin term itself is a possessive derivative, indicating the stone was named after its discoverer. Thus, the term's journey is not one of semantic composition from roots, but of toponymic or personal attribution, transforming a proper name into the common noun for a specific, naturally occurring volcanic glass.
Analysis
This word is a loanword adopted as a simplex unit. It does not contain productive morphemes in English that can be segmented from its current spelling.
Examples
The ancient tool was crafted from a single piece of sharp, black obsidian.
Obsidian is formed when lava cools extremely quickly, preventing crystal growth.
Many museums display obsidian mirrors used in Mesoamerican rituals.