Possible Clues:

• Misleading clue
• The ruby on her finger is just to put one off
• The ruby on her hand is just to put one off in fishy fashion
• Embarrassed, being wrong about hard misleading clue
• Distracting literary device
• Whodunit misdirection
• False lead
• Misleading information
• An irrelevance about Lawrence initially being inaccurate
• The ruby on her finger is just to put you off