Gemoetry not rendered the same when in particle system?

I am working on a seamless texture with gold coins to have as a plane underneath a particle system.
But I am getting different results depending on if the geometry is in particle systems or just duplicated
somewhat by hand. For instance, if you look at the closest coins in the images the ones in the particle system are much brighter. If any of you have come across this, please let me know.
I have made sure that the geometry is in pretty much the same place, I added an image to show to both geometry particles (green) and geometry duplicated by hand (red).

Gold Coins spread out using particle-systems:


Gold Coins Spread out by duplicating Geometry:

Both of the above were geometry particles are in green and geometry duplicated by hand are in red.