1713, "what sparkles" (often of gems, wits, or women), agent noun from sparkle (v.). In the modern hand-held fireworks sense, from 1905.
The New York Board of Fire Underwriters has issued a warning against the storage, sale and use of a new form of fireworks now on the market. These are known as "electric sparklers," are made in Germany, and come to this country in metal lined cases each containing 120 dozen of pasteboard boxes with 12 sparklers in each box. The Board's warning says that while the sparklers appear harmless, the solid incandescent mass is intensely hot and readily communicates fire to any inflammable substance it may touch. [The Standard (weekly insurance newspaper), Boston, May 4, 1907]