A dragon's egg is a fireworks pyrotechnic star  which first burns for a period for a visual effect then explodes with a loud report. Manufacture of this effect became controversial because of the toxic compounds once used, particularly lead tetroxide (Pb3O4). 
Nowadays, however, bismuth trioxide or bismuth subcarbonate are commonly used as more environmentally friendly substitutes for lead compounds to achieve the effect, and its occurrence in fireworks displays has since become much more common.
Because of how heavy an individual bismuth atom is, a shell or cake containing mainly dragon's eggs (and therefore enriched in bismuth) is often noticeably heavier than a similar device containing other effects.
- Croteau, Gerry; Dills, Russell; Beaudreau, Marc; Davis, Mac (2010). "Emission factors and exposures from ground-level pyrotechnics". Atmospheric Environment. 44 (27): 3295. Bibcode:2010AtmEn..44.3295C. doi:10.1016/j.atmosenv.2010.05.048.
- Ledgard, Jared (2006-02-22). The Preparatory Manual of Black Powder and Pyrotechnics. ISBN 9781411685741.
- Linda D. Hall (2006). Brands and Their Companies: Consumer Products and Their Manufacturers with Addresses and Phone Numbers. Thomson Gale. ISBN 978-0-7876-8951-3.
- Chris Mocella; John A. Conkling (15 January 2019). Chemistry of Pyrotechnics: Basic Principles and Theory, Third Edition. CRC Press. pp. 51–. ISBN 978-1-351-62655-2.
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