You'all are mixing up two things. Or maybe even three.
Some cars have projector-type low beams. If you look at the headlight from the front you see a lense rather than a reflector with a globe in the middle of it. Projector-type headlights cut glare. They have the side effect that the lense can cause a rainbow effect at the edge of the beam. So right on the upper edge of the low beam you see blue.
Then there's the type of globe in it. There were old-style filament globes which these days look yellowish like sunlight. Then there were halogen globes with quartz envelopes which were much whiter in the light they put out because they are able to run the filament at a higher (ie, bluer) temperature. Some of these are coloured blue for no other reason than to show off that they are halogen bulbs. Some of these have "xenon" on the packaging, indicating use of xenon as the gas in the envelope. But they are still filament-style bulbs. The best and most efficient bulbs are high intensity discharge (HID) bulbs where the light isn't being generated by heating up a filament but by a high voltage discharging through an halogen gas.
If its a projector-type lamp it has a HID bulb. Look at the front of the light and you see the lense instead of a reflector and bulb. The beam is bluish, with a rainblow at the upper edge of the beam.
If its a reflector type lamp it would only have a HID bulb in it if it has been fitted by the owner. No manufacturer I know of puts HID globes in reflector-type headlamps as standard. So that's unlikely but possible. If it has a blue coloured beam it may simply have a blue-tinted halogen globe in it.
Some cars have projector-type low beams. If you look at the headlight from the front you see a lense rather than a reflector with a globe in the middle of it. Projector-type headlights cut glare. They have the side effect that the lense can cause a rainbow effect at the edge of the beam. So right on the upper edge of the low beam you see blue.
Then there's the type of globe in it. There were old-style filament globes which these days look yellowish like sunlight. Then there were halogen globes with quartz envelopes which were much whiter in the light they put out because they are able to run the filament at a higher (ie, bluer) temperature. Some of these are coloured blue for no other reason than to show off that they are halogen bulbs. Some of these have "xenon" on the packaging, indicating use of xenon as the gas in the envelope. But they are still filament-style bulbs. The best and most efficient bulbs are high intensity discharge (HID) bulbs where the light isn't being generated by heating up a filament but by a high voltage discharging through an halogen gas.
If its a projector-type lamp it has a HID bulb. Look at the front of the light and you see the lense instead of a reflector and bulb. The beam is bluish, with a rainblow at the upper edge of the beam.
If its a reflector type lamp it would only have a HID bulb in it if it has been fitted by the owner. No manufacturer I know of puts HID globes in reflector-type headlamps as standard. So that's unlikely but possible. If it has a blue coloured beam it may simply have a blue-tinted halogen globe in it.
however when they are on... unless you bend down paralell to the lights, you cant see much just a white circle, and when you do.. you get blinded 
