opal

名词 opal:

1. a translucent mineral consisting of hydrated silica of variable color; some varieties are used as gemstones

1. Opals are milky gems.
   蛋白石是乳白色的宝石。

o.pal

n.（名词）
A translucent mineral of hydrated silica, often used as a gem.
蛋白石：一种非晶质氧化硅，含有明显的变色晕彩，常被用来当作宝石

来源：
Middle English opalus
中古英语 opalus
from Latin
源自 拉丁语
alteration of Greek opallios
希腊语 opallios的变化
probably from Sanskrit upalaô
可能源自 梵文 upalaô
from upara- [lower]
源自 upara- [较低的]
from upa [below] * see upo
源自 upa [在底下] *参见 upo

【引伸】
o.paline.