Head over to Varrock and look for Reldo, the helpful librarian of Varrock Castle. He's usually found in his library towards the north side of the castle, and ask him about the Imcando Dwarves. He explains to you that they were almost completely wiped out from the Barbarian attacks, but some may still exist.
Reldo tells you to check the cliffs near Port Sarim, and that you'll probably need a Redberry Pie to get the Dwarf to help you. You can either buy a Redberry Pie from another player, or cook it yourself, provided that you have level 10 Cooking.
Once you've got the pie, head to Port Sarim, just a short distance south of Falador. Continue walking south until you reach a cliff where you should see a small house and a Dwarf named Thurgo. Ask him if he'd like some Redberry Pie, and speak with him again to ask if he will make you a sword. He says that if you get him a picture, he could probably smith it for you.
Now go back to the Squire in Falador and ask him if there's a picture of the sword. He tells you that Sir Vyvin has one in his cupboard in the Castle. Go inside through the main entrance and climb up the ladder. Climb up the stairs in the next room, and upstairs should be a small room to the south. Open the cupboard inside and search for a Portrait of the sword.
Now that you've got the portrait, bring it to Thurgo to let him look at it. He says that he needs 2 Iron bars and 1 Blurite ore to make a copy of it. You can either smith or buy the iron bars from another player. Blurite ore can be found in the cave right near Thurgo's house, but it may be a little tricky to get at.
Inside the cave entrance are Muggers, which you can probably slip by quite easily. Next is a group of Pirates, which are more difficult, along with a few Hobgoblins. After following the passage for awhile you will come across an area covered in ice. Toward the east side of the cave can be found 2 Blurite rocks, guarded by many level 57 Ice Warriors and several level 53 Ice Giants. It may be wise to bring some food, and hopefully you will leave with a Blurite Ore .
Hint: If you want to get an extra sword, get 4 Iron bars and 2 Blurite ores. After Thurgo makes the first sword, drop it and have him make another. Before you talk to the Squire, drop a sword or he will take both. (thanks for the tip, Grogrim!)
When you have the needed items, give them to Thurgo who will make you a Blurite Swordto bring back to the Squire. After giving him the sword, you're finished!