opal

复数：opals

1. Opals are milky gems.
   蛋白石是乳白色的宝石。
2. It was a round opal, red and fiery, set in a circle of tiny rubies.
   那是一块圆形蛋白石，红红的，象火焰一般，上面镶着一圈红宝石。

The OPAL Collaboration
Updated Opal Opacities
Tunable Inverse Opal Hydrogel pH Sensors
OPAL Equation-of-State Tables for Astrophysical Applications
The barite-opal-organic carbon association in oceanic particulate matter
Fabrication of High-Quality Opal Films with Controllable Thickness
Unique pathway of expression of an opal suppressor phosphoserine tRNA
High efficiency of CdSe quantum-dot-sensitized TiO2 inverse opal solar cells
A simple method for the rapid determination of biogenic opal in pelagic marine sediments
A review of the Si cycle in the modern ocean: recent progress and missing gaps in the application of biogenic opal as a paleoproduct...