Purple Dragon Heraldry?

[Zelknolf]

Alright - two questions that I'm not finding a good answer for in source books, and maybe someone knows, and can save me the horror that is looking for answers in Candlekeep forums.

Question 1 - what is the purple dragons' coat of arms? In artistic representations I found, it's Sable, A Dragon Purpure Rampant (which violates the rules of heraldry, something the Cormyr probably wouldn't do, but also something good ol' Greenwood might not know about. Maybe it's funky shading and that Sable should be an Argent?) but I never found a passage that outright says "Ahoy, here it is, in simple heraldic language!"

Question 2 - Noble houses that serve in Cormyr are supposed to show their colors and the Purple Dragon's colors on "halves" of their banner -- does anyone know if this is party per pale or party per fess? (the wording has me thinking it's not party per bend or party per sinister.)