Historical clue formulations

• Gemstone with biological roots — 2026-07-01
• Bit of wisdom — 2026-02-01
• Bit of wisdom — 2025-12-28
• June birthstone — 2024-01-16
• Oyster's gem — 2023-10-09
• Cultured sort? — 2023-09-07
• Bit of wisdom — 2023-03-15
• Oyster's prize — 2022-09-12
• See 4-Down — 2022-07-15
• Gem from an oyster — 2022-05-30
• Gem from an oyster — 2022-04-04
• One hanging around Queen Elizabeth? — 2021-12-26
• Oyster's creation — 2021-04-05
• White gemstone — 2020-11-23
• Beauty — 2020-09-19
• Off-white shade — 2020-07-15
• Gem in an oyster — 2019-12-30
• June birthstone — 2019-09-04
• Gem strung on a necklace — 2018-10-01
• Bit of wisdom — 2018-07-27
• Gem whose authenticity can be checked by rubbing it against the teeth — 2016-05-16
• Fine example — 2015-08-22
• Shade of white — 2015-03-24
• Unit of wisdom? — 2013-08-23
• [30] — 2013-01-16
• Cultured gem — 2011-09-07
• Beauty — 2010-07-02
• ___ onion — 2009-02-18
• Shade of gray — 2007-05-02
• Masterpiece — 2007-04-29
• It may start as a grain of sand — 2007-02-07
• Gem of an oyster — 2006-10-16
• Small treasure — 2006-08-02
• Stickpin head — 2004-12-02
• Unit of wisdom? — 2004-11-28
• Oyster's prize — 2003-09-22
• June birthstone — 2002-09-08
• Oyster's prize — 2002-04-29
• Modern June birthstone — 2001-08-05
• Oyster's prize — 2001-06-11
• Necklace item — 2001-04-24
• Oyster's center — 1999-01-18
• Precious one — 1996-12-01
• Shade of gray — 1996-05-22
• Bit of wisdom — 1995-09-15
• Janis Joplin, to her fans — 1995-09-10
• Rock's _____ Jam — 1995-07-02
• 5 point type — 1995-03-05
• Hester Prynne's daughter — 1994-03-19
• Oyster catch? — 1994-01-09