Grape agate gets its name from the clusters of tiny purple or green quartz crystals that form in a botryoidal (spherical) habit resembling a bunch of grapes. However, the name of this mineral is not true to what it actually is mineralogically--it is not technically an agate because there is no banding, but is actually a chalcedony. 

Mined on the small island of Sulawesi in Indonesia, grape agate is found within bluish clay that is covered in andesite rock (a volcanic rock). Andesite is formed from ancient volcanic lava that cooled in seawater, creating pockets within the andesite rock for the grape agate to then grow from mineral-rich water seeping into the voids. It first appeared on the market in 2015. 

Indonesia 

Size: 3.38 x 1.63 x 1.63 inches

Weight: 1.45 oz.