what is actually the antimatter how does it look..

If there were enough antimatter for us to observe with the naked eye, it would probably look just like ordinary matter. One of the big mysteries of science is why there is so much more matter than there is antimatter. It is currently supposed that there must have been a built-in imbalance right from the creation of the Universe. When matter and antimatter meet, both are annihilated, so it might be somewhat difficult for us (who are composed of protons and electrons) to observe antimatter (composed of antiprotons and positrons) because both us and the antimatter we were trying to observe might simply vanish in a flash of pure energy. Here is an article which tries to explain what antimatter is: http://encyclopedia.kids.net.au/page/an/Antimatter

In particle physics,antimatter is the extension of the concept of the antiparticle to matter where antimatter is composed in the same way that normal matter composed of particles. For ex. a positron (which is the antiparticle of electron) and an anti proton can form an antihydrogen atom in the same way that an electron or proton make a normal hydrogen atom. Further more mixing Matter and Antimatter can lead to annihilation of both of them in the same way that particles and antiparticles does thus giving rise to high energy photons or other particle or antiparticle pairs. Theoretically ,it could be a myriad of colors , just as standard matter can be variety of colors; however we haven't seen enough of it, to truly say- when we have synthesized antimatter , it has been a matter of a few subatomic particles, CERN for example has stated that at full operation capacity it would take about 100 billion years to synthesize even one gram of antihydrogen - even if it behave something like hydrogen, it would be invisible on the visible spectrum anyway. Beyond that antimatter has problem of containment which is an incredible difficult exercise with even few antiprotons, let alone a visible amount of antimatter. if you have any query please free to comment.