Apparently these bulbs did not have the correct vacuum or gases inside, it is common in these situations for the bulb to darken or turn blue, you can see that the one you took out of the other lamp was already blue
Halogen bulbs can easily melt or lose vacuum, but this black is caused by skin oil overheating the quartz (glass) of the bulb. This could also be caused by lack of Iodine/Bromine, halogen gasses that extend the life of the bulb, by collecting evaporated Tungsten, and redepositing it on the filament. I have seen air causing halogen bulbs to fail. The bulb turns gray and blue and the filament turns black.
When I was 9 back in 1998 or '99 my mother had a 300 watt halogen torchiere from as far back as I could remember, the lamp may have even dated from before I was born in '89 and I changed the bulb not knowing you were supposed to use a paper towel or clean cloth to keep skin oils off the quartz and clean it with rubbing alcohol if you do touch it with bare hands, and about a week later while I and my younger sister were doing our homework, the bulb shattered and my arms were burned painfully with flying hot quartz. Luckily the home we lived in at the time was built in the early 1940s with tile floors which almost certainly contained asbestos. I remember those halogen floor lamps being available at almost any major retail store (Kmart, Montgomery Ward, Wal-Mart) for around $20 to $30 or so and many had a full range dimmer or off -low-high switch and they came with a wire guard to help keep curtains and what have you from blowing onto the bulb and lighting the house on fire; the lamp my mother had didn't have the wire guard or a glass shield around the capsule.
Whenever I change out a burnt-out bulb for a new bulb, regardless of how careful I think I am to avoid touching the glass with bare fingers, I always wipe the bulb down with methylated spirits OR Isopropyl alcohol-soaked lint-free cloth.
If you do accidentally touch a halogen capsule with your fingers, you can clean it off with rubbing alcohol prior reinstall and you shouldn't have a problem. I have heard that liquor alcohol can also be used to clean halogen bulbs after being touched but preferably rubbing alcohol. But in either case, if you can find an LED replacement for the double ended halogen like in this video, you should try it. I am quite sure that the bulbs lost vacuum and burned out that way.
Some have contaminants on the glass from the factory, so I normally clean them with methylated spirits before installing.
Apparently these bulbs did not have the correct vacuum or gases inside, it is common in these situations for the bulb to darken or turn blue, you can see that the one you took out of the other lamp was already blue
Had this happen a couple times with my work light that looks like this i converted to a 13w 2 pin fluorescent light
Halogen bulbs can easily melt or lose vacuum, but this black is caused by skin oil overheating the quartz (glass) of the bulb. This could also be caused by lack of Iodine/Bromine, halogen gasses that extend the life of the bulb, by collecting evaporated Tungsten, and redepositing it on the filament. I have seen air causing halogen bulbs to fail. The bulb turns gray and blue and the filament turns black.
Also, if air got into the bulb, it would have burned out almost immediately.
When I was 9 back in 1998 or '99 my mother had a 300 watt halogen torchiere from as far back as I could remember, the lamp may have even dated from before I was born in '89 and I changed the bulb not knowing you were supposed to use a paper towel or clean cloth to keep skin oils off the quartz and clean it with rubbing alcohol if you do touch it with bare hands, and about a week later while I and my younger sister were doing our homework, the bulb shattered and my arms were burned painfully with flying hot quartz. Luckily the home we lived in at the time was built in the early 1940s with tile floors which almost certainly contained asbestos.
I remember those halogen floor lamps being available at almost any major retail store (Kmart, Montgomery Ward, Wal-Mart) for around $20 to $30 or so and many had a full range dimmer or off -low-high switch and they came with a wire guard to help keep curtains and what have you from blowing onto the bulb and lighting the house on fire; the lamp my mother had didn't have the wire guard or a glass shield around the capsule.
Whenever I change out a burnt-out bulb for a new bulb, regardless of how careful I think I am to avoid touching the glass with bare fingers, I always wipe the bulb down with methylated spirits OR Isopropyl alcohol-soaked lint-free cloth.
If you do accidentally touch a halogen capsule with your fingers, you can clean it off with rubbing alcohol prior reinstall and you shouldn't have a problem. I have heard that liquor alcohol can also be used to clean halogen bulbs after being touched but preferably rubbing alcohol. But in either case, if you can find an LED replacement for the double ended halogen like in this video, you should try it. I am quite sure that the bulbs lost vacuum and burned out that way.
The light an LED would put out would be nowhere near as good as the halogen one. Halogens are already pretty efficent too
Interesting. Looks like when a high pressure sodium light turns off.
Cool