The color of the dmt usually comes from impurities like fats or other plants stuff if it has been extracted.
Just like olive oil has a yellow color the fat from acacia or mimosa can have a yellow or even reddish hue depending on compounds.
I have extracted white, yellow, red and even rather black dmt but it always worked no problem.
If its in crystal form it should be pure enough.
Also dont forget that even white dmt crystals can be more impure than yellow ones.
You cant really tell purity from color but usually the less tan the better.
See this thread for example
https://www.dmt-nexus.me...&m=779575#post779575