Possible Clues:

• Tropical hardwood – I rook (anag)
• African hardwood
• Tropical African hardwood tree
• Timber tree that's very good, almost smooth on the outside
• An African hardwood
• A light-coloured African hardwood
• Hard wood often used as a teak substitute
• Inventor of early music synthesizer
• A hardwood from tropical Africa
• Hard metal cut around fine, hard wood