Diamonds may be the hardest natural substance known to man but it is not that strong. If you hit a diamond with a hammer the diamond will break. Not a very effective weapon if the other person is carrying a sword. Then you have to take into account that you would need a diamond big enough to make the sword.
People have found industrial diamonds big enough for a dagger or short sword, but a one hand or long sword? No! Also, the melting point of diamond is so high, it is not really possible to soften it enough to actually make the sword.
If some one slashed at you with a steel sword, and you parried with the diamond sword, the results would be a steel sword with a 1 inch nick/dent in it, and a bunch of diamond dust. You could make a steel sword and serrate the edge with sharpened diamonds. It would be cool looking, sharp, and strong. It would still cost a fortune, but much less then a sword made completely of diamond.
Another Answer
Flaws in industrial diamonds make them much easier to break apart, and much harder to fabricate in single forms.
Making a sword out of diamond is impractical, if you intend to use the sword as a weapon.
You can make a diamond sword in Minecraft by placing two diamonds above a stick in the crafting table.
you can make a sword, and bow. the sword can be in wood, stone, iron, gold, or diamond. you need three of these and a stick to make. diamond is the best to make the bow you need some string and sticks.
By itself, nothing If you have wood, you could make a diamond sword, a diamond shovel, a diamond hoe or a jukebox
no you cant!!!!
You Cant Myth-busters already tested it .
stone sword, iron sword, gold sword, and diamond sword
The number for the diamond sword is 276 . so put this is chat- /give (your name w/out parentheses) 276
You cant get a sword in MGS3
Nope
diamond sword or axe
Enchanted with 999999999 sharpness on a diamond sword. This is possible with plugins.
No. You can't make a solid diamond sword there needs to be high pressure and heat to even make a shapeless diamond. To add onto this answer-even if it was possible, diamond would not be a suitable blade material. It is hard, but that does not mean it is strong. It could not withstand the lateral forces swords are subject to.