The colors vary depending on the element used to produce them, from white to yellow to gold. The oxidizing substances are potassium nitrate, chlorate, and perchlorate. Magnesium is used to produce white sparks. The colors and intensities of the fireworks are determined by the burn rates of the different elements. Sodium, a common ingredient in fireworks, imparts a gold color and can also mask other colors. Magnesium is a rare metal used in fireworks, although its alloy with aluminium is called magnalium.

Sparkles in Fireworks Come From Iron Powder

Simple shells, meanwhile, consist of a thin paper tube filled with a star or sparkler compound. Those made of simple stars are usually dime-sized, or pea-sized. These fireworks are enclosed by black powder to prevent them from fluttering in all directions. During an explosion, the bursting charge in the shell ignites the star-shaped outside, sending it shooting out in all directions. The result is a sparkling sphere.

Multi-break fireworks, on the other hand, contain multiple stars, each with a bursting charge inside. The middle break of a multi-break firework must ignite at the point of greatest force in its trajectory, while the first and third breaks should blow slightly before or after. Timing can cause a firework to detonate too close to the ground, so great care is taken to design the fuses in a way that ensures the best possible fireworks display.