Historical clue formulations

• Banded mineral seen at many a street fair — 2026-03-31
• Black gemstone — 2025-10-07
• Jet-black stone — 2025-09-13
• Jet-black stone — 2025-07-22
• Gemstone whose name comes from the Greek for "claw" — 2025-04-29
• Black gemstone — 2025-02-20
• It might make a cameo — 2024-04-05
• Gem used in intaglio — 2024-03-09
• Shade of black — 2023-06-07
• Variety of agate — 2022-11-12
• Type of chalcedony — 2022-10-28
• Deep black — 2022-10-05
• Mineral with parallel bands — 2022-06-30
• Rock with colorful bands — 2021-12-12
• Dark rock — 2021-01-07
• Traditional gemstone for a seventh wedding anniversary — 2020-10-15
• Black gem with bands — 2020-01-20
• Black, banded gemstone — 2019-06-03
• Black gemstone — 2019-04-15
• Inky stone — 2019-03-17
• Black gemstone — 2016-12-12
• First gemstone mentioned in the Bible — 2016-01-10
• Cameo material — 2015-12-01
• Jet black — 2015-11-22
• Cameo stone — 2015-10-18
• Jet-black gem — 2015-08-17
• Black rock — 2015-08-16
• Black ring material — 2015-04-17
• Inky — 2014-12-18
• Material used in many high-end chess sets — 2014-08-14
• Cameo stone — 2014-04-02
• Jet black — 2014-03-02
• Cameo gem — 2013-11-18
• Jet black — 2013-11-15
• Panther figurine material — 2013-04-14
• Deep black gem — 2012-08-21
• Stone for a Cancer, traditionally — 2012-08-18
• Chalcedony variety — 2012-07-04
• Jet-black gem — 2012-04-11
• Black — 2011-05-26
• Black — 2011-04-22
• Jet black — 2011-02-13
• Cameo gem — 2010-11-10
• Gem with colored bands — 2010-09-27
• Common cameo stone — 2010-02-09
• Ornamental stone — 2007-12-20
• Cameo choice — 2007-03-17
• Stone used for chess sets — 2006-05-02
• Black stone — 2006-04-05
• It might make a cameo appearance — 2005-11-19