Stackable Rings

I came across this first picture today and I want every single ring I see!  I love stackable rings and can't resist adding to my own collection.  I especially like simple bands with diamonds in them, but who doesn't?!  

Source: zsazsabellagio.blogspot.com via Ali on Pinterest

Source: habitualbliss.tumblr.com via Ali on Pinterest

Source: maxandchloe.com via Ali on Pinterest

Source: shop.nordstrom.com via Ali on Pinterest

Source: everythingfab.com via Ali on Pinterest

Source: stylemepretty.com via Ali on Pinterest

Are you a collector?  Do you have a favorite?