Historical clue formulations

• Milky and iridescent — 2026-05-23
• Like a moonstone — 2010-10-23
• Iridescent — 2010-10-01
• Milky and iridescent — 2008-10-17
• Iridescent — 2004-06-13
• Iridescent — 2002-05-04
• Like moonstones — 2000-08-04
• Having a range of colors — 2000-03-04
• Prismatic, as a stone — 1997-05-04
• Resembling a birthstone — 1995-09-10
• Iridescent — 1994-07-08