in AM, also use 美国英语亦用 semiprecious
ADJ [usually ADJ n] （宝石）半珍贵的，次贵重的，半宝石的 Semi-precious stones are stones such as turquoises and amethysts that are used in jewellery but are less valuable than precious stones such as diamonds and rubies. （宝石）半珍贵的，次贵重的，半宝石的