dead quartz

例句：

1. 1. This mineral is known for its unique color and hardness.
   这种矿物以其独特的颜色和硬度而闻名。
2. 2. Dead quartz is often used in jewelry making due to its high hardness.
   由于其高硬度，死石英常用于珠宝制作。
3. 3. The crystals are formed when hot magma cools quickly, leaving behind the dead quartz.
   这些晶体是在岩浆快速冷却时形成的，留下的是死石英。