i've bought one recently. It was a 7kg salt lamp, cost me about rm 140. Not so sure how you tell them apart but someone told me that the best salt lamps are the ones that come from poland... and the so-so ones are the ones from China.
I don't think the colour makes any difference, more of a preference.
I've smelt the "after the rain" smell when i've come back from work in my room. really nice.. but as to whether its ionizing....beats me.
and if you do buy one, you MUST keep the light on for 24/7 or the "lamp" will melt. Moisture from the air will "attack" it so the lamp melts and you get salt crystals on your table.. happened to me when my bulb fused and it took me 2 weeks to find a new one.
In the End, we will remember not the words of our enemies, but the silence of our friends.
--Martin Luther King