The data presented here is an aggregated estimate from multiple sources and applies to an average smartphone model (2018-2022). Content mass varies significantly by manufacturer and battery chemistry.
- **[S1]** Orton Geological Museum - The Ohio State University: General element uses and sources (your original source). [ortonmuseum.osu.edu/gallery/minerals-your-cell-phone](https://ortonmuseum.osu.edu/gallery/minerals-your-cell-phone)
- **[S2]** USGS Geologic Survey (GIP 167): Mineral uses and source countries. [pubs.usgs.gov/gip/0167/gip167.pdf](https://pubs.usgs.gov/gip/0167/gip167.pdf)
- **[S3]** He et al. (2019) / Cucchiella et al. (2015): Metal content (g/unit) in smartphones (academic/industry report basis).
- **[S4]** Fairphone / CompoundChem / Cobalt Institute: Recycling rates and supply chain risk assessments.
- **[S5]** IEA / Statista / Cobalt Institute Forecasts (Projected Demand Growth %): Projections for global demand growth to 2030, primarily driven by **EVs and Energy Storage**.