Chances are what you saw was one of the newer metal halide fixtures.
Other HID types:
Mercury vapour (MB): White, but with a distinct blue or blue-green tint. Different phosphors used on the bulbs means the colour does vary significantly, but it's still blueish generally. Very poor CRI though, and extremely high colour temperature.
High Pressure sodium (SON): Can be seen in fixtures simiar to those you've illustrated, but they have a distinct golden yellow colour to them. Efficiency's significantly higher than MB lamps.
Relatively recently, true white high pressure sodium lamps (WhiteSON - I *think* with the SDW prefix - that I am unsure of though, it could be a prefix excusive to Philips), the light from these is virtually indistinguisable from incandescent. These tend to be lower wattage lamps (<200W), and I have seen them in similar fixtures in our local supermarket.
Low Pressure Sodium (SOX): The most easy to identify type of lamp. Very distinct monochromatic yellow colour (580nM). These lamps are VERY efficient (126lm/W for a 38W lamp) and modern eamples have extremely long service lifetimes (up to 20K hours), but the CRI of zero means that they're almost exclusively used in security and streetlighting...and the one in my bedroom. Though that only gets used rarely..basically because the ballast makes a noise like a power station once it's warmed up, and the *bzzzzzzzzz* tends to get a little distracting.
Also, you've got your metal halide lamps (MBI, HQI, MHN, CDM, HCI, HPS and probably a number of others): These can have pretty much any colour of white you want depending on the metal halide mixture used, ranging from a distinctly yellowish 3000K lamp, right up through pure white to a crazy 10'000K (and higher I belive), including strange variations like green and peach colours too. The only drawback I've found with these lamps is that the equipment does tend to be expensive - and that the luminare needs to be well designed. Basically because the lamps can, and occasionally do explode if they're used past the end of their rated lifetime. Larger bulbs tend to have an integral blast shield, but the smaller ones muse be used in a totally enclosed fixture in case that happens.
Hopefully this info's of some use. Great information on all of these types of lighting can be found at
Lamptech.
What are those lights in many new stores? (WHITE!)
Linear Mode
