I have washing detergent that looks just like your stuff. Would you like to see a picture?
At some point, to illustrate my point, I posted a picture with 5 different powdery substances, of which just one was MDMA. Just by looking at the picture outsiders couldn't tell reliably which one was the real deal and which one was the above mentioned washing detergent.
You'll get many responses on investing to a testing kit. Please do.
While you haven't ask yourself:
How well do you know the person who provided you this shit?
Is he your best friend?
Have you seen him using _this_ same stuff and not die?
If he is not your best friend and _you_ die or get permanent injuries, is it possible to track him down for punishment (ie. how motivated is he to avoid selling bad stuff).
Ask the same on your source's source. Oh, you can't tell? Then consider it as answer: His source couldn't care less what happens to people using the shit he sells, those people are not able to trace it to him anyway, he is safe on his way to bank.
Besides substance identification threads are not allowed in BL, the moderator will most likely lock this thread soon.