white vs light pink color of MgO

Recently I ordered some high purity MgO, which is light pink in color. However, the old powder I was using was white. MSDS also suggests that it should be white. Can anyone explain the reason of two different colors of MgO of same purity.


Thanks in advance


PS- I suspected it to be due to absorption of moisture earlier, but it is not the case. Even on heating at 800 C, does not change the color.


