Earth’s core could contain helium from the early solar system. The noble gas tucks into gaps in iron crystals under high pressure and temperature.

Numerous iron-containing minerals exist on Earth (Table 1 & Figure 2 ... Journal of Plant Nutrition & Soil Science 168, 558–-573 (2005). Behrenfeld, M. J. & Kolber, Z. S.

A team of geologists has unveiled the largest iron ore ... This table highlights the sheer magnitude of the deposit and its transformative implications for both science and the economy.