There Would Be No Fireworks Without Rocks And Minerals

There would be no fireworks without rocks and minerals.

An aerial fireworks burst is produced by launching a fireworks shell high into the air, where an explosion occurs. This explosion propels brightly burning particles (known as “stars”) in many directions. Each streak of light in the firework is a burning “star” flying through the air.

Coal and saltpeter (potassium-nitrate) are used to create gunpowder, the fuel that allows the stars in the firework to burn. Nitratine, a highly reactive mineral, is the natural form of sodium-nitrate and serves as an oxidizer for fireworks, supporting the fuel’s combustion.

The vibrant colors in a firework don’t come directly from the burning fuel, but metallic minerals that are deliberately added in very small amounts to the mix. As the fuel burns, the metal atoms in the crystal structure absorb energy, emitting a specific wavelength of light that we perceive as a distinct color.

The element barium will produce green light. Barium is obtained from barium-sulfate, known as the mineral baryte. The baryte group also includes celestite, or strontium-sulfate, used to produced purple fireworks.

The elements strontium and lithium will produce red light. Strontium is the 15th most abundant element in the Earth’s crust. Only two minerals, however – celestite and strontianite – contain strontium in sufficient quantities for commercial use, and these minerals are found predominantly in sedimentary rocks.

The element calcium will produce yellow light. Named from the Latin word meaning “lime,” calcium is – unsurprisingly – very common in limestone rocks composed of calcite and dolomite.

The elements sodium and cadmium will produce yellow light. Most sodium is obtained nowadays by processing the mineral halite, also known as sodium-chloride or common table salt. Sodium occurs in many other minerals as well, including amphibole, zeolite and cryolite. Cadmium minerals are very rare and include cadmoselite (a cadmium-selenide), greenockite (a cadmium-sulfide) and otavite (a cadmium-carbonate). Cadmium substitutes for zinc in sphalerite (zinc-sulfide) and similar minerals, so most is recovered during the industrial processing of zinc, copper and lead ores.

Close-up of greenockite, the only ore mineral of cadmium.De Agostini via Getty Images

Burning magnesium and aluminum will emit a brigt white light. Magnesium is chiefly obtained by electrolysis of magnesium-chloride, which can be obtained in virtually unlimited quantities from the oceans or salt lakes. Magnesium is also obtained in smaller quantities from the magnesium-bearing minerals dolomite, magnesite, kieserite and brucite. Other magnesium-bearing minerals include carnallite, cordierite, and diopside. Aluminum is the most abundant metal element in the Earth’s crust and can be obtained from Bauxite ore. Bauxite is a complex mix of the minerals gibbsite, boehmite, and diaspore, formed as less stable minerals like feldspar and mica react with water.

Purple light is also emitted from excited copper and manganese atoms. Copper is found in many minerals that occur in deposits large enough to mine. These include azurite, malachite (both copper carbonate hydroxide minerals), chalcocite (a copper-sulfide), acanthite (a copper-silver sulfide), chalcopyrite and bornite. Most copper comes from chalcopyrite, a copper-iron sulfide mineral. Manganese easily reacts with water and air. On Earth, manganese is never found as a free metal, but it is found in a number of minerals. The most important of these minerals is pyrolusite, a mineral consisting essentially of manganese-dioxide and the most important ore of manganese.

The element cobalt will produce blue light. Cobaltite is a sulfide mineral composed of cobalt, arsenic, iron, and sulfur. Although rare, it is mined as a significant source of the strategically important metal cobalt. Traces of cobalt can be found also in common nickel minerals like carrollite, a sulfide of copper and cobalt, and linnaeite, a cobalt-sulfide.