To best answer your question it would be most useful to see the inside "face-in" side of the mask, so that we could see where you could attach hardware.

Off the top of my head, I'd say look for something like a clear plastic pincer that could grasp the mask by the inner corners of the eye holes.
Or maybe some art wire from a craft store, it could hang from one of those picture hangers and be bent into a shape that the mask could set on.

Though I think it looks great on the table.

Could you mount a dummy head to the wall (like a mannequin head, or a display stand for a wig) and set the mask on it? Even a single bracket that extends out, with some sort of padded disk facing up on the far end of the bracket might work. Then you wouldn't have to put any kind of hardware or adhesive at all on your mask.

Maybe a wreath hanger would work too.

I have a similar mask and since I was never going to wear it I glued a loop of fishing line/filament to the inside of the forehead area and have had it hanging like that for years.
There may also be a way for you to hang it from the eye openings w/out damaging the mask. It's beautiful!

I have several masks like this but they have ties attached from the side. If you don't want to put holes in the side to put ribbon through you can attach the ends of ribbon to interesting buttons and "button hole" through the eye openings and tie it from there. I have mine hanging off the corners of a mirror in a dressing room. It is how I saw them displayed when I bought them. Yours is gorgeous!

Stretchy plate hangers? The kind that has the two prongs at the bottom and has a stretchy part that extends to the top of the plate.

Tie fishing wire through and around the eye holes.

http://amazingplatehanger.com/

you can get them at many craft stores and they are removable with water. not sure how easy it would be on this but i think it could be done without damage.

what about a single "L" bracket? the base that is attached to the wall would be hidden by the 'forehead' and the bottom portion of the L would support the 'nose' of the mask?

otherwise I think kiki713's suggestion of gluing fishing line to the forehead (and then hanging it from a picture hanger-style hook) is probably the safest way to support the mask...

What is the mask made of? Is it rigid? I've used something called Framepegs to "balance" things on the wall. You just drill the Framepegs into the wall (they sell an acrylic version which should not damage the mask) and let the edge of the mask rest on them. I have also seen a version of these things at Lowe's. Google them and you can see what they are typically used for, but it will get your imagination going.

Another option is to put up one of those short display shelves, lean the mask up against the wall and have the nose part just hanging down off the front edge.
(a display shelf like this, with a front lip: http://www.target.com/12-Traditional-Black-Wood-Shelf/dp/B001FD8TY0/ref=sr_1_1?ie=UTF8&searchView=grid5&frombrowse=0&node=1038576&keywords=wall%20shelf&field_browse=1038576&searchSize=30&id=12%20Traditional%20Black%20Wood%20Shelf&field_availability=-2&refinementHistory=subjectbin%2Ctarget_com_age%2Ctarget_com_gender-bin%2Ctarget_com_character-bin%2Cprice%2Ctarget_com_primary_color-bin%2Ctarget_com_size-bin%2Ctarget_com_brand-bin&searchNodeID=1038576&field_launch-date=-1y&searchRank=target104545&searchPage=4&field_keywords=wall%20shelf)

[geez that's a heck of a long url-sorry!]

Oh, go ahead and drill.

I was thinking that a padded hat stand would work, mounted on the wall. I have seen them before in costume shops used to display wigs. If you don't feel like making one, here is one that I found that I think would be interesting with or without padding. (Although I think the padded would help protect the mask from slipping.)

http://www.delmarhat.com/hatstand.html

a mask that i have like that has ribbons on the side that are actually glued on inside, and i'm pretty sure others i've seen had the same thing, so it wouldn't necessarily be damaging it ... it's not hanging now but it did for more than a few years, by the ribbons, without them breaking or damaging the mask, so if you use a strong glue it ought to be ok. maybe find out the kind of glue that they use when they make them?

From the pictures you posted it looks like a plate hanger stretched to a correct position for hold would do the trick. Just in case that doesn't work though, I hope you get other ideas posted soon! Good Luck!

OOoo I have that mask (although, it's alot less adorned)! It was one of those impulse buys that you should avoid when walking around Venice.
Usually when they sell those masks, it has a little triangular hook taped to the inside of the top of the mask so you can nail it on the wall. But, I didn't want to put nails on the wall so I just set it on top of my book shelf. If you put it high enough on the wall, you will barely see the nail (probably, hopefully). Plus, you could paint over the nail and the hook with paint to make it less visible.

Thanks everyone for your good ideas on how to hang this up! I'm going to try the ribbons and/or the wire through the eyes first because I have those items on hand. If that doesn't work I'll go out and look at the other suggestions to see if they might work. I feel like a dunce for not thinking of those options myself, but hey, that's why I submitted the question. Thanks again!