The Affair Of The Pink Pearl
First published in The Sketch (Oct 1, 1924) with known title, then as Blunt's Brilliant Detectives in 3 issues of Ellery Queen's Mystery Magazine (US - Apr. 1960, AUS - Jun. 1960 & UK - Jun. 1960).
[R.Austin Freeman's Dr. John Thorndyke] "Tommy and Tuppence are approached by a distraught Beatrice Kingston-Bruce and her mother - a precious pink pearl has been stolen from their houseguest, Lady Laura Barton. Tommy investigates, in the guise of Dr. John Evelyn Thorndyke, the great medico-legal detective created by R Austin Freeman (1862-1943) – who just happens to possess an incomparable intellect, a vast knowledge on a number of subjects, and dashing good looks."
3rd story in the collection .