I need help to find the gem that celio need for the machine he is fixing..

Did you mean the Sapphire plate?

If you do, it is found at Dotted Hole. (use Cut at the front hall)

First of all go to island 6 then find a place with a temple/shrine thing with dots on the front of it. Use HM Cut on it.

Go inside and fall through the hole and you will find your self in a room with 4 holes at each side go to the top hole and fall through it.

Then the left one, next to the right one and finally the bottom one you will reach the Sapphire stone.

When you try to grab it a rocket scientist will take it from you and the rocket base will be accessible.

It's in Dotted Hole on Six Island. Cut the Door and enter.

Fall down the hole, then fall down the holes in this order; up, left, right, down.

Then some professor will come down and take the Sapphire, but give you the other password to the Rocket Warehouse on Five Island.

Go there and navgate through the warehouse and take back the Sapphire. Give it Celio, and you can Trade with Ruby and Sapphire.

Go to island six and go to the door with six dots on it .

Then use Cut and it will open then go to the first hole on the top then when you fall go to left then fall and go right then fall and go down.

A man will steal the other gem and give you the second passworg then go to the Team Rocket hideout and try your best through the arrows.