铀

Left-side metal radical - the 5-stroke compressed form of 金. Indexing radical, anchoring 铀 in the periodic-table family of metal characters coined in the 19th and 20th centuries (钠 sodium, 钾 potassium, 镭 radium, 钚 plutonium). Carries the meaning directly: 铀 names uranium, a heavy radioactive metal.

Right 由 supplies the sound - yóu straight through, no drift. The 'from / by' meaning is irrelevant; 由 is a pure sound-tag chosen by 20th-century chemists transcribing the European 'uranium' as yóu → 铀. Same phonetic family: 油 oil, 邮 mail, 釉 glaze - all carrying yóu.