Green’s Dictionary of Slang

snowflake n.1

[snow n.1 (2a) + flake n.1 ]

cocaine.

[US]Bisbee Dly Rev. (AZ) 26 Aug. 6: These hopheads [...] will do anything [...] to get money to buy opium, morphine, ‘snow flakes’ and similar drugs.
[US]J.E. Schmidt Narcotics Lingo and Lore.
[US]Mad mag. Sept. 45: Johnny Snowflake?!? The Yayo?!? Booger Sugar?!?