Four-leaf clovers

The brooches in the image are actually four-leaf clovers, not three-leaf clovers. Four-leaf clovers are a rare variation of the three-leaf clover, and are said to bring good luck to the finder. The brooches in the image appear to be made of gold or gold-plated metal. They have a round shape with four petals that come to a point at the tip. The brooches are sitting on top of a white box.

It is difficult to say for sure what the brooches are called without more information. They could be called four-leaf clover brooches, gold clover brooches, or shamrock brooches. Shamrock is another word for clover.