What is "occlusions"

Usage examples of "occlusions".

Mineral occlusions were now strings and veins of beryl, shading here and there into lumps of raw emerald big as Investors' heads, crisscrossed with nets of red corundum and purple garnet.

The distortions and occlusions of the Protoculture wraiths could not stand before that raw power, and the Masters saw-at last where their target lays.

Since Afra could 'port himself with an assist from the station's generators, he availed himself of those periodic longer occlusions when great Jupiter, or several of the smaller moons, made traffic in or out of Callisto impossible.