To be exact...Black Slate from Mena, out near Big Forks.
This is a pure black slate, which to the unaided eye has an exceedingly fine texture and a remarkably smooth cleavage surface(very sexy) with a light luster. It is both carbonaceous (yeah, right!) and magnetitic: does not effervesce (puts middle finger out) with cold dilute hydrochloric acid (I'm guessing it does), is very sonorous (speak English freak scientist!), and very fissile (English, damn it!)
Under the microscope this slate shows a matrix of muscovite (Boris!), with a very brilliant aggregate polarization (LIAR!) and an unusally fine texture and great homogeneity (snicker).
Quartz grains are few and not over 0.01mm (Yeah,...we all know what that means??) in diameter. Rutile (that can't possibly be a real word) needles unusually minute. Many opaque (not clear) particles of irregular shape, some of which are pyrite (they now run Indian Casinos, correct...The Pyrite Tribe??) others magnetite, and some coaly (can't be a word) or graphitic matter.
So to sum up:
Arkansas has slate.