If you really want to see green, you need a well-aged color improved lamp with a nicely blackened arc tube.

Mercury vapor bulbs don’t normally look green to the human eye

They normally don't, but aged lamps with heavily blackened arc tubes can look greenish.  In addition, /C phosphored lamps can shift to a green color as the phosphor wears out.  In both cases, these are going to be high hour lamps.

Chinese Regent/Cooper mercury lamps do tend to go dim and green quite early compared to better made bulbs.

If you really want to see green, you need a well-aged color improved lamp with a nicely blackened arc tube.

/W type lamps can do this too...usually just a little bluer to the eye.