Silica Pearl Locations on the Island Map

Silica Pearls are found all around the bottom of the cliff that circles the coast of The Island map.  There are two minor exceptions seen as X in the image below.  Most silica pearls are found in the Northwest corner of the map.  There is only one interior location where you can find the silica pearls, and that is a bend in the river at the southern edge of the snow biome, located about Lat 31.1  Lon 33.2.  If you are looking for black pearls shells, there are none on The Island, they can only be harvested from creatures. 

X indicates the absence of Silica Pearls.  The circle at NW corner is where they are most abundant.