topouzid Themetal particles you're seeing is actually mercury (the liquid metal element) and is required by those lamps in order to work. If you light it up, mercury evaporates inside the tube and makes continuity between the two poles (anode/cathode). And since mercury is highly toxic, poisonous and carcinogenic, if you break this lamp while it was on, it's crucial to leave the room immediately and aerate it, and then carefully pick the broken glass light (wearing gloves if possible) and pick any traces of liquid mercury you'll find near the broken light, and throw it as far as possible.

topouzid Purpleis more like UV, the luminous intensity is indeed very low @3V. On my batch there were 40 orange LEDs and no yellow LEDs instead of 20 orange and 20 yellow.