Dictionary.net

• A fossil tooth colored a bright blue by phosphate of iron. It is used as an imitation of turquoise, and hence called bone turquoise.

2010 - New Age Dictionary Database
By Oddity Software

• A fossil tooth colored a bright blue by phosphate of iron. It is used as an imitation of turquoise, and hence called bone turquoise.

1913 - Webster's Revised Unabridged Dictionary
By Noah Webster.