A Form of Carbon That Is a Very Hard Gemstone
This page is the CodyCross answer for the clue below from Treasure Island, Group 1025, Puzzle 4 (Hooks and Peglegs).
Question is: A Form of Carbon That Is a Very Hard Gemstone
and the answer is: DIAMOND
Word Meaning:
DIAMOND — (uncountable) A glimmering glass-like mineral that is an allotrope of carbon in which each atom is surrounded by four others in the form of a tetrahedron.
Definitions from Wiktionary.