Related Clues:

• Po-faced about school figure mixing up colours
• Cover image on Pink Floyd's 'The Dark Side of the Moon'
• It separates light into the colour spectrum
• Pointy thing that makes light go off in a new way
• Transparent block
• Square, primarily, in proper solid shape
• Beam-splitting crystal
• Solid figure in pair is married
• Object that separates light into a spectrum
• Could this throw light on teacher returning during the afternoon?
• Certain decorative paperweight
• Solid shape, proper round sphere, primarily
• Spectrum former
• Reflector in some telescopes
• Glass that makes a rainbow