Time it takes to turn purple/black

[Kaister]

I've read in pill reports instances where people have had a colour change (on dropping reagent on to scrapings) which is almost immediate, like 1 second.
I have had the perfect colour result of purple/black, but it occurs gradually over 1 or 2 minutes.
Is there anything wrong with how long this colour change takes?

 

[DiscoStu]

Real MDMA will turn black instantly. DXM will turn black after about 8-10 seconds.
It's not MDMA.

 

[Mr. Sticky]

How quickly does it turn purple (before turning purple-black)? If it turn purple within 10 seconds, and then slowly black over time, it's probably MDxx

 

[Kaister]

It starts to turn purple immediately, but then gradually gets darker and darker in purple colour until it is very dark purple/black.
I guess it must be MDxx.

 

[Mr. Sticky]

DXM shouldn't turn purple at all, so I'd guess it was MDxx as well.
The higher the binder to MDxx ratio, the slower the reaction since their is a lower percentage of reactible material in the scraping.