It doesn't look like a pearl. Most people don't realize that pearls found in the wild are almost never round. They are always baroque. Things that get tumbled in the surf are often round. We've seen a number of rocks, glass and other things here on the forum people have found on the beach. So far, nobody has found a pearl.
Also, pearls don't come from oysters in the true sense. They come from mollusks. They also don't have a grain of sand in them.
Some kind of round white pearls can be found in caves, but they don't have organic origin, just calcareous concretions, and I have looked at geological maps of Comox grounds: these are not calcareous, but I have noticed some basalt around, a stone where rare round calcite concretions are found (I add a photo of these). You can try to put a vinegar drop on the surface, and if that foam (quickly rinse with water if it does), maybe this object can be one... So, many fishs have aragonite concretions (otoliths) in their heads, but they are never round.