Historical clue formulations

• It's multifaceted — 2022-04-20
• Ruby, e.g. — 2021-05-02
• Rock — 2015-08-01
• "Rock" — 2012-08-10
• Opal or topaz — 2010-02-22
• Diamond or ruby — 2008-10-13
• Set piece? — 2008-09-20
• Ring thing — 1997-12-21