We'll cover two families together, because they share a theme: the valuable metal is locked inside tough rock that needs heavy heat or acid to crack open — and both are stars of the green-energy story.

Carbonates

The definition: a carbonate is a mineral built on the carbonate group — carbon joined to oxygen (written CO₃). Handy test: many carbonates fizz when you drip weak acid on them. That fizz is carbon-dioxide gas escaping.

• Rare earth elements are the headline. The world's biggest rare-earth deposits sit in carbonatites (rare volcanic carbonate rocks). The mineral bastnäsite gives the metals used in the powerful magnets inside EV motors and wind turbines.
• Magnesite and dolomite give magnesium and heat-resistant furnace linings.

Silicates

The definition: silicates are built on silicon joined to oxygen — the most common building block in the Earth's crust (about 90% of it). Most silicates are just gangue (waste rock), but a few are valuable ores.

• Spodumene is the big one: the main hard-rock source of lithium for batteries.
• Beryl gives beryllium (used in aerospace and defence); garnet is mined as an abrasive.

Getting lithium out of spodumene takes real energy: you roast it (heat it until its structure changes) and then dissolve the lithium out with acid.