The Topaz Post Office opened in 1885, closed in 1922 and reopened in 1926. The post office is located on the Robert William Mckay Family Ranch and is operated by the family.

According to Wikipedia, the name Topaz was derived from the color of the local quaking aspen trees.

Fifty people lived in Topaz in 2010 according to the United States Census.

Source: Wikipedia

Perhaps there are quaking aspen trees in Topaz, but the only topaz colored trees we noticed were cottonwoods.