U
- Ulexite: NaCaB5O9·8H2O – German chemist George Ludwig Ulex (1811-1883)
- Ullmannite: NiSbS – German chemist and mineralogist Johann Christoph Ullmann (1771–1821)
- Uytenbogaardtite: Ag3AuS2 – Dutch mineralogist Willem Uytenbogaardt (1918 - 2012)
- Uvarovite: Ca3Cr2(SiO4)3 – Russian Count Sergei Semenovitch Uvarov (1765–1855)
Read more about this topic: List Of Minerals Named After People