Concave Diamonds #557, Northwood   Updated 12/6/2011
Stretch glass collectors also claim this pattern, but it sometimes shows up in Carnival auctions. The pattern is a soft quilting effect, always with a stretch-type iridescence. Complete water sets, like the celeste example above, will include coasters for the tumblers and a lid for the pitcher. Found mostly in celeste with occasional vaseline and rare russett/olive pieces showing up.
Water set, 14 pieces (with coasters and lid)

Celeste blue, 550 (2007), 575 (2009),
   400, 500 (both 2010)

Celeste blue, with original Jewel T box, 550 (2008)

Water sets, 7 pieces (with lid, no coasters)

Celeste blue, 250 (2004), 200 (2010),
   140, 400 (both 2011)

Water sets, 7 pieces (no coasters or lid)

Celeste blue, 275-350

Vaseline, 1,300 (2000), 800 (2006), 700 (2007)

Water set, 8 pieces (6 tumblers, lid)

Celeste blue, 250 (2006), 385 (2010)

Water pitcher

Vaseline, 800 (2008)

Tumblers

Celeste blue, 33 (2008), 150 (2009),
   20 (2010), 10, 13, 20 (all 2011)

Olive/russet, 450 (2002)

Vaseline, 65, 115 (both 2009), 105 (2010),
   80, 85 (both 2011)

Tumble up (water jar and small tumbler)

Celeste blue, 200 (1997), 525 (2000)

Olive/russet, 155 (2004), 100 (2009)

Vaseline, 350 (2001), 800 (2003), 475 (2009)

Tumble up tumbler only

Blue opaque, 80 (1998)

Celeste, 100 (2004), 30 (2010), 20 (2011)

Olive/russet, 100 (2004), 45 (2009), 13 (2011)

Vaseline, 50 (2002), 85 (2006), 10 (2009)

The 6-inch ruffled vases were whimsied from the tumble up bottle.

Vases

Celeste blue, 125 (2000), 55 (2009), 65 (2011)

Citrine, 65 (2005)

Ice blue, 45 (2007)

Russet/olive, 95, 120, 275 (all 2003),
   85 (2004), 130 (2007)

Vaseline, 250 (1997), 450 (2003)

I don't know if this pickle castor was made by Northwood or is from the same line, but, in marigold, it sold as Concave Diamonds at a 2009 auction for $545.