It is gorgeous! I thought you had framed/sashed the blocks with gray, but it is just laid out on the gray?

I love the gray, sash it & border it with the same.

Stark black would also work beautifully. Think of all those bright on black Amish quilts!

:-D

I think your quilt is wonderful. It looks like jewels! I would use a black border. I have just completed a string top but it is multicolor. My next one will be similar to yours, thanks for the idea.

Pretty blocks! For borders, I'd add a black one, say 2", then add a 1.5" once color from blocks border. Finish by adding another black border about 4".
Surely anything you decide will be great! The black with the bright colors is just great!

This is one of the prettiest string quilts ever!!! About the border, maybe one of the darkest blues from the quilt? Perhaps a narrow strip of odd-length colors between two dark borders? Who knows. You've done great so far so I'm sure whatever you do will be perfect:)

It is beautiful. What if you used a black border and a multi colored binding? I don't know but it is a keeper!

it looks like faceted jewels! gorgeous! I would be tempted to go with a black border for the pop myself...

Another vote for black. It is just stunning the way it is, with black, even more so. GREAT job, by the way.

If you want to "contain" all of the colors, go for black, if you're thinking contempory, pick one of the bright colors and go for it!!
This is going to be a very striking quilt, which ever you choose!

I love the way you've used the strings to create such great dimension. I think a plain black border would be very effective. Your colors are so vivid!

I would do a thin black solid border and then the coloured strings and then another slightly wider border of the same black.

Lay it out on one side to see how it looks before sewing.