Maybe it was originally a Mother Daughter watching hot air balloons? But certainly as titled is fitting too, along with Grandmother Granddaughter Day pin and of course a Aunt Niece day pin. 

It has been priced based on the sale I saw of the woman only, generally similar, back turned for $40. It appears to be a gold plated base metal with possibly a tin based alloy that the girl is crafted from. 

The two were detached when received. A circular portion of the girl mounted to a knob of the lady and the fit was loose and even with adjustments, the two would certainly detach again in the near future, so they now have been fused with a hearty silver solder bond assuring the will not risk detaching anymore.