Just after coming off the cutting wheel. The opals have absorbed water and have become completely transparent all the color is gone
Four days later. The water has started to evaporate leaving Micro condensation inside the opals. This makes the opals look foggy or milky. The color is starting to come back there when you can see it in several of the stones.
Showing the changes in Hydrophane opal as it dries out over time. This is typical of Ethiopian opal from the Welo province.