I am not sure if you mean the Unown wall, but there are Unown ruins (called Solacean Ruins) to the right of Solacean Town
You cannot find a Braille decoder sheet in any of the Pokemon games. Braille is very simply and easy to translate if you print off a Braille alphabet sheet for reference.
Using a braille chart, you can match up the braille with their corresponding letters to find out what they mean. Here is a braille chart: http://en.wikipedia.org/wiki/Braille
You will see the chamber and a wall with braille on it. The braille says 'Dig Here' You will soon gain access into the first sealed chamber. The wall will open (eventually) allowing you to catch Regice.
Go to wikipedia, they have a braille dictionary.
Braille can be found in many of the Pokémon games. You can easily find out what it means by looking up the Braille alphabet.
You cannot find a Braille book in Pokemon FireRed. You can however find the Braille alphabet to make notes from inside Mt.Ember. Mt.Ember can be found just north of Knot Island.
You can find Terry Pratchett books in braille online through websites like the National Library Service for the Blind and Print Disabled or organizations like the Braille Institute. You can also check with specialized braille bookstores or libraries that offer braille materials for purchase or borrowing.
Hardest metal is diamond because wayyy back when they decided to do test. They take car of diamond and ran it to a metal wall at the speed of light. The brick wall dissolved. Then they took a metal car and ran it into diamond wall at speed of light. Car dissolved. They then took speed of light car and drove it into wall made of metal at the speed of diamond. The earth shook but everything dissolved. Then they took diamond wall and drove it into a speed of metal wall and created muffin. This concluded that diamond is the hardest metal
In the packet that you bought the Ruby with, there should be a braille code. If you cannot find it then go to this page. http://en.wikipedia.org/wiki/Braille
You can find things written in Braille in the ancient ruins in the Pokemon games. To read it, you can simply look up the Braille alphabet.
You go inside his cave, and walk straight ahead and it's on the wall there.
Walk to the middle of the cave and use flash.