Can't find solar fragments

[rapid gyro]

I have spent weeks (in-game) clearing the ocean floor looking for solar fragments. The very first day I had some success but since then there's been nothing. I can't upgrade my underwater tools without first finding solar fragments so I can make solar cores. Am I missing something?

[strange drum]

Have you smash rocks? Otherwise, Solar Cores are sold from Cho Oyu's Oracle Chamber.

[rapid gyro]

No I haven't smashed any rocks. I'll try that now thanks.

[lyric topaz]

You get them from the beach and ocean rocks.