The classification of brass depends on the crystal structure that they have. Depending on the structure, it decides the property that the brass parts reflects. The combination of copper and zinc determines the characteristics. When the atoms of copper and zinc combine at a specific temperature and ratio, it prepares a unique crystal. There are more than 60 types of brass alloys that are specified by the European Norm Standards. As per the crystal structure, there are mainly 4 types of brass:

Alpha Brass>65<35This type of brass is malleable and can be worked with in cold state. It forms a homogenous crystal structure and forms a uniform solid composition. It can be easily cold worked like welded, rolled,  pressed, forged, etc.
Alpha Beta Brass55-6535-45This kind of brass is also called as duplex brass as it contains both the alpha and beta structure. It is both hard and strong and is cheaper. Also it is workable at high temperature and is resistant to cracking.
Beta Brass50-5545-50Beta brass is hard and strong so it can only be casted in hot state. This high ratio of copper and zinc makes it the brightest type of brass.
White Brass<50>50This is the most brittle type of brass and is also referred to some type of nickel and silver alloy. The white brass does not have yellow color but it is rather silver like.