Green’s Dictionary of Slang

prop n.3

[Du. proppe, a brooch, a skewer]

1. [mid–late 19C] a scarf- or tie-pin.

2. [late 19C] a woman’s brooch.

3. [20C+] a diamond or other valuable piece of jewellery.

In compounds

prop-getter (n.)

1. [1900s] a pickpocket in general.

2. [1900s–30s] (also stone getter) a stealer of diamond and other brooches.

prop-man (n.)

[1930s–40s] (US) a thief specializing in small pieces of personal jewellery.

prop-nailer (n.) [nail v. (1)]

[mid–late 19C] a thief who steals scarf- or tie-pins, brooches and similar small pieces of jewellery.

prop worker (n.) [worker n.1 (1)]

[1940s] (UK Und.) a thief specializing in tie-pins or other pieces of small jewellery.