Fetching details from the dictionary...
magnesium (Mg)
疲労回復にはマグネシウムが良いと聞いた。
I heard magnesium is good for recovering from fatigue.
実験でマグネシウムを水に入れた。
In the experiment, I put magnesium into water.
この部品は軽くて、主成分はマグネシウムだ。
This part is light, and its main component is magnesium.