black·board 
(blăkbôrd′)
(blăkbôrd′)n.
A smooth, hard, dark-colored panel for writing on with chalk.
- crystalize
- crystall-
- crystall-
- crystal lattice
- crystalliferous
- crystalligerous
- crystallin
- crystalline
- crystalline lens
- crystallinity
- crystallite
- crystallitic
- crystallizable
- crystallization
- crystallize
- crystallizer
- crystallo-
- crystallographer
- crystallographic
- crystallographical
- crystallographically
- crystallography
- crystalloid
- crystalloidal
- crystal pleat