Strong's G2930 · Greek

κρύσταλλος

krustallos · kroos'-tal-los

from a derivative of kruos (frost); ice, i.e. (by analogy) rock "crystal"

Scholarly Lexicons

Abbott-Smith Manual Greek Lexicon

 2 κρύσταλλος , -ου, ὁ ( κρύος , frost ), [in LXX: Jb 38:29 , Ps 147:6 , ( 17 ), Ez 1:22 ( קֶרַח ), etc.;] crystal : Re 4:6 22:1 .† 

G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain