The 'Here's to Never Growing Up' hitmaker, who married the Nickelback frontman, 39, at Château de La Napoule in the South of France on 1 July 2013, admitted she is still in shock over his generous gift.
The 29-year-old singer shared a photograph of them, in which she is wearing the dazzling piece of jewellery, on Twitter on Thursday (31.07.14), with the caption: ''I still can't believe my 1 year anniversary gift. 17 carat emerald cut. Wow. I love my hubby (sic)''
The new sparkler is larger than the 14-carat pear-shaped engagement ring the rocker proposed to the blonde beauty with in early 2012, but slightly smaller than her 20-carat emerald wedding ring, which is estimated to have cost approximately $1 million.
The 'Complicated' singer, who was previously married to Sum 41 star Deryck Whilbley, recently admitted she can't wait to start a family with Chad, but insisted they are too busy at the moment.
She said: ''I'm really focused on my career at the moment.
''Down the road, I would love to be a mom, just not right now.''
Chad also previously said: ''We both want [children]. We just need to find a time we're both at home to get around to it.''
Corgan took to Instagram to confirm rumours of new Pumpkins material, saying the first songs could arrive as early as May.