Why are there no gems in the second area to open the portal?

I think it's because you have to clear the first area but if that is already done then I have no clue

I can't find the gems and I've cleared the whole of first world and nearly all of second world

Did you click repair or something like that on the portal itself I found it & cleared 90% of everything but didn't click that 1st so no gems showed up as soon as I clicked it tho they all appeared.

You have to press the portal and a button that says “Repair” shows up. Click that, after it is done repairing the gems should appear. If they don’t it may be a glitch or this is not true and I just got lucky.