sevum

例句：

1. 1.The sevanum is a rare and valuable mineral found in the earth's crust.
   塞维农是一种稀有且珍贵的矿物，存在于地球的地壳中。
2. 2.The sevanum was discovered by accident during a geological survey.
   塞维农是在一次地质调查中偶然发现的。
3. 3. The sevanum has been used in ancient civilizations for its healing properties.
   塞维农在古代文明中被用于其治疗属性。