Hey guys, how do you get the saphire?

First go to island 6. Go to the bottom where the big stone door is. Go up to it and use cut with one of your pokemon. Look at your brail chart and go down the holes in the order the stone with the brail writting says. The Saphire will be there. A scientist will take it and tell you the second password to the rocket base on island 5. Go to island 5 and get into the rocket warehouse. Do the puzzle and fight the 2 admins. Just above them is the scientist. Defeat him to get the saphire.

First you have to go to Icefall cave on four island and help Lorelei kick out the rockets. Then, go to six island and go to a cave called Dotted Hole. Use cut on the silver door and it will open. Go inside and go down the hole. Now go down the holes in this order: North, West, East, South. You will now be at the sapphire. Go up to it and press A. Before you can take it, a scientist comes after you and takes the sapphire, but gives you the other password to the rocket warehouse on Island five. So, follow him back to the rocket warehouse and go inside. Battle your way to the back of the warehouse and defeat the scientist. He will give you the sapphire gem. Return to Celio and give him the gem. Now, the Network Machine will be completely functional and you will be able to trade with Pokemon Ruby and Sapphire games! Plus, you will now be able to get Mewtwo in Cerulean cave!
Hope I helped!

After you bring the ruby to celio,make sure you have at least 100 diff types of Pokemon then talk to prof oak he will upgrade your dex and then go to 1 island, swim across the water to mt. Ember and go to the place where the 2 rokets were standing go in the cave and find the saphire.