We have as our prompt the title and first line of a poem attributed to the oddly named Wishes for Sale.
If I could catch a rainbow
Use it as you wish at the start or within your gem. Leave your URL with Mister Linky as usual. All that remains then is to say 'hi' to your fellow writers and see what they've made of it!
Over at Carry On Tuesday Plus you can read the poem and if it takes your fancy, listen to Peggy Lee singing 'Sing a Rainbow'.