amethyst

Concise Bible Dictionary:

What we know as amethyst (not necessarily the same stone).

Strong’s Dictionary of Hebrew Words:

Transliteration:
’achlamah
Phonic:
akh-law’-maw
Meaning:
perhaps from 2492 (and thus dream-stone); a gem, probably the amethyst
KJV Usage:
amethyst

Jackson’s Dictionary of Scripture Proper Names:

dream-stone (literally I shall be brought back—as from a dream)