Background: I am a fourth year math graduate student in the US.
Perhaps you will think this question silly, but I intend for it to be a serious question.
In teaching courses such as calculus and analysis, I frequently find myself wanting to use colored chalk. Unfortunately, all the colored chalk I can get seems to be of exceptionally poor quality. It tends to be very light and brittle, and quite difficult to erase. Too be honest, it's nearly unusable. (I suspect it's been designed for children, rather than teachers.)
Many of the topologists at my university have a much better type of colored chalk, but none of them seem to know where to buy more of it. I'm aware that Hagoromo chalk exists, but I'm looking for something that's more easily obtainable. I don't need it to be the best chalk in the world, just something useable would be great.
That being said, can anyone recommend a brand that is both easily obtainable and reasonably useable? Links to online retailers are wonderful, but any guidance whatsoever is much appreciated.