noun🔗Share강옥An extremely hard mineral, a form of aluminum oxide with the chemical formula Al2O3, that occurs in the form of the gemstones sapphire and ruby; it is used as an abrasive."Because of its hardness, corundum is used in sandpaper to smooth rough wood. "경도 때문에 강옥은 거친 나무를 매끄럽게 하기 위해 사포에 사용됩니다.mineralmaterialgeologysubstancechemistryscienceChat with AIVocabulary GamePractice Reading
