I'm sorting through used Lego bricks and found that in some stacks of blue bricks there are slightly different shades. I can't find a common shade of blue that matches and I'm not certain that it's not just fading or discoloration due to time and exposure. However there seem to be only 2-3 distinct shades which makes me think they're actually different colors.

Can anyone help identify what color they might not be if not Blue?

For comparison, I've put some of these blue bricks next to my color board of common blueish colors: from left to right Bright Light Blue, Sand Blue, Medium Blue, Medium Azure, Dark Azure, Blue, and Dark Blue

Note the one with the arrow seems very similar to the one 2 to the right of it and is duller & darker than the reference Blue piece, though not as dark as Dark Blue.

2 Answers 2


It looks like these darker are the same bricks in Blue that have simply "yellowed" over time, which changes the shade of the color. Another answer explains the reason behind this process.

  • Once I can purchase hydrogen peroxide again I'll try using that but for a much shorter time than I do for whites. I was/is reluctant to retrobrite non-white pieces but for those I don't feel comfortable selling them as blue
    – Scott
    Commented Apr 2, 2020 at 23:00

As Alex mentioned, part of the variance can be attributed to yellowing, especially the ones pointed at with the arrow. For the remainder, I think you are looking at variations in color introduced in the production process ... see this question for more details: LEGO color discrepancies and tint variations

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