You have to use cut
To enter dotted hole, use cut at the door to get inside it.
use cut
Cut open the door with the HM cut 01
Head to four island go in icefall cave find HM7 use it to go up the waterfall go to the ladder save lorelei go back to dotted hole use Cut on the door and your inside.
try to take the sapphire inside the dotted hole and the scientist that was once blocking the door to the dotted hole will tell u (to get inside the dotted hole form it into a question and type it up in the bar above)
Head to four island go in icefall cave find HM7 use it to go up the waterfall go to the ladder, go through the litlle doorway and save lorelei. Then go back to dotted hole use Cut on the door and you should be inside.
it is called dotted hole use cut on the door and go inside and go thourgh the maze to get the sapphire
take a Pokemon that knows the move cut and then go through the menu and select it
then go to the left hole then to the rigth hole then the downer hole .
You take the hole in the middle and then the top then the left then the right then the bottom and you'll get the sapphire.
you need 2 use cut on the door to open it
Go inside the dotted hole cave on six island inside you can find the sapphire it will be taken from you! Follow the robber to five island and go inside the rocket warehouse inside defeat the robber and you will get the sapphire.