Compositions comprising a continuous phase of at least one polypropylene; within the range of from 5 wt % to 50 wt % of a mineral hydroxide filler by weight of the composition, having an aspect ratio within the range of from 5 or 6 or 8 to 20 or 40 or 100 or 200 or 800 or 1000; and within the range of from 5 wt % to 40 wt % of a olefin block-containing copolymer by weight of the composition. Also described is a method of forming the compositions comprising combining the components as “masterbatches” or as neat ingredients, or some combination thereof.