Beryl

A hard beryllium aluminum silicate.
Beryllium is rare so usefulness as structural material is limited.
Al₂Be₃[Si₆O₁₈], hexagonal, Mohs 7.5 to 8.0

• 🟩 Green form of beryl is the widely known emerald.
• 🟦 Blue for is widely known aquamarine.
• 🟨to🟧 Yellow to orange: heliodor (or "golden beryl")
• 🟧to🟪 orange to pink: morganite.
• 🟥 red: just "red beryl"
• ⬜️ colorless form: goshenite

Related

• Bromellite: BeO, Mohs 9, hexagonal
• Topaz Mohs 8 (defining mineral) … another unusually hard widely known silicate but avoiding elemental scarcity

External links

• https://en.wikipedia.org/wiki/Beryl