Green’s Dictionary of Slang

money; cite 1851 refers to fraudulent ‘gold’.

1851		Bell’s Life in Sydney 26 Apr. 3/4: [He] submitted the ‘shiny’ to a small chemical process.
1856		C. Reade It Is Never Too Late to Mend 1 35: We’ll soon fill both pockets with the shiney in California.
1876		St Louis Globe-Democrat 19 Jan. n.p.: The young man [...] feels impelled to ask his friends if they have any ‘rocks’ or ‘shinies’ about them.