Where Does a Blue LED Come From? We Rewound It Step by Step | Rewind Factory #05
Short answer
- Blue LED light comes from gallium nitride layers only about 20 atoms thick.
- Gallium behaves like aluminum, so most of it is recovered from bauxite, aluminum's ore.
- 2.2 lb (1 kg) of red earth holds 10,000+ chips' worth, yet only about 4% was recovered (at 50 ppm average).
Also calledwhat are blue LEDs made ofwhere does gallium come fromhow LED chips are made
Video
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Explained
In the video
- 0:00Blue light before dawn
- 0:35The light-emitting layers come apart in the reactor
- 1:31Gallium, a silvery metal
- 2:22White and red merge again at the alumina refinery
- 3:11Why an aluminum factory produces gallium
- 3:52Red earth crosses the sea
- 4:12To a red mine, by satellite
- 4:27Rain over more than ten million years
- 5:04Fast-forward back to the blue light
Where does the material inside a blue LED come from? Starting from one blue light in a city before dawn, we rewind through the chip, the crystal-growing reactor, the metal gallium, an alumina refinery, a sea voyage, and a red mine.
The route
| Place | What happens there | When |
|---|---|---|
| A city before dawn | Blue LEDs are shining | Today |
| Chip factory | A round sapphire wafer is cut into chips about 0.3 mm across (one example size) | Today |
| Crystal-growing reactor | On sapphire at about 1000 °C, gallium nitride layers are grown from trimethylgallium and ammonia. The light-emitting layers mix in indium at a lower temperature; each is only about 20 atoms thick | High-brightness blue LEDs reached practical use in 1993 (Japan Science and Technology Agency (JST)) |
| Gallium refining | Gallium at 99.99% is purified further for electronics. In research, crystallization methods exceeded 99.99999% (one example; factories use different methods) | Today |
| Alumina refinery (with gallium recovery) | Bauxite is dissolved in a hot, strongly alkaline solution (caustic soda) to make white alumina. Gallium is recovered from the leftover liquid with resin and electrolysis | Large-scale Bayer-process production since the 1890s (International Aluminium Institute (IAI)) |
| Sea route (example: Guinea to China) | Bauxite travels by ship, about 13,000 miles (about 21,000 km; estimate) | In 2024, about 70% of China's bauxite imports came from Guinea |
| A mine in Guinea (example) | Red bauxite is dug in open pits (some bauxite is not red) | Satellite image: January 2026 |
| Underground, where rock meets red earth | Tropical rain washes out what can move, leaving aluminum, iron, and gallium | Large deposits are thought to need more than 10 million years, or several intense weathering periods |
This is one example route. Most gallium is recovered from bauxite, but some comes from zinc ores and other sources, and we cannot tell where the gallium in any single LED came from.
The numbers in detail: one chip holds about 1.8 µg of gallium (with 4 µm of gallium nitride; 1.4–3.7 µg for 3–8 µm). One chip's worth of red earth is 0.03–0.07 g. The estimates assume 0.3 mm chips, a density of 6.1 g/cm³, an average of 50 ppm, and full recovery. If the average were 40–80 ppm, the recovered share would be 2.5–5.0%.
What you will learn
- Blue LED light comes from layers of gallium nitride mixed with indium, each only about 20 atoms thick
- Gallium sits just below aluminum on the periodic table and behaves so much like it that gallium rides along in bauxite and is recovered at alumina refineries (some also comes from zinc ores)
- The gallium in 2.2 pounds (1 kg) of red earth equals the amount in more than 10,000 LED chips, yet only about 4% of the gallium in all mined bauxite was recovered (calculated assuming an average of 50 ppm)
Sources
Where the facts and numbers in the video and on this page come from.
References
- U.S. Geological Survey (USGS) Mineral Commodity Summaries 2025: “Gallium”
- Siming Lu et al., “Research on the Source and Recovery Methods of Gallium,” ICSOBA 2023
- U.S. Patent US6533838B1 (2003); Kefeng Pan et al., Materials 2018, 11, 2308
- Reuters via Baird Maritime (July 1, 2025), “Guinea bauxite shipments hit record on strong China demand”
- Smithsonian Human Origins, “Homo sapiens”
- Semiconductor Engineering, “Phosphors Turn Blue LED Lights White” (Katherine Derbyshire, 2013)
- Simon Cotton, “Trimethylgallium,” Molecule of the Month (February 2023, University of Bristol)
Links
- The Nobel Prize in Physics 2014 — press release, popular and advanced information, and the Nobel lectures by Hiroshi Amano and Shuji Nakamura (in Japan)nobelprize.org/prizes/physics/2014/summary
- Japan Science and Technology Agency (JST), research highlights (in Japanese)jst.go.jp/seika/bt47-48.html
- Lai Wang et al., arXiv:1611.07972 (measurements of a commercial blue LED chip)arxiv.org/abs/1611.07972
- U.S. Geological Survey (USGS) Mineral Commodity Summaries 2026: “Gallium,” “Bauxite and Alumina,” “Indium,” “Nitrogen (Fixed)—Ammonia”pubs.usgs.gov/periodicals/mcs2026/mcs2026-gallium.pdf
- Foley, Jaskula, Kimball & Schulte (2017), “Gallium,” U.S. Geological Survey (USGS) Professional Paper 1802-Hpubs.usgs.gov/pp/1802/h/pp1802h.pdf
- International Aluminium Institute (IAI), “Sustainable Bauxite Residue Management Guidance” (2022) and related pagesinternational-aluminium.org
Voice, music, art
- Music (OpenTracks): “時計図書館” by MATSU / “考え中” by 鷹尾まさき / “海底の神殿” by KK
- Sound effects: Freesound CC0 / Kenney
- Fonts: Zen Maru Gothic / Inter / M PLUS Rounded 1c (SIL OFL)
