tt en ▁stone , ▁the ▁fin est ▁ab ras ive ▁available ▁at ▁the ▁time . ▁ ▁It ▁is ▁also ▁used ▁to ▁pol ish ▁j ew el ry ▁and ▁in ▁to oth p ast es . ▁Its ▁more ▁common ▁use ▁is ▁as ▁a ▁fill er , ▁as ▁used ▁in ▁pl ast ics , ▁paint ▁and ▁rub ber . ▁ ▁S ources ▁Rotten stone ▁has ▁been ▁extens ively ▁worked ▁in ▁South ▁Wales ▁along ▁the ▁out c rop ▁of ▁the ▁Car bon ifer ous ▁Lim estone , ▁particularly ▁within ▁the ▁Bre con ▁Be a cons ▁National ▁Park . ▁It ▁occurs ▁at ▁the ▁top ▁of ▁the ▁sequence ▁where ▁the ▁Upper ▁Lim estone ▁Sh ales ▁have ▁been ▁weather ed . ▁In numerable ▁work ings ▁were ▁initi ated ▁and ▁later ▁abandoned ▁during ▁the ▁course ▁of ▁the ▁nin ete enth ▁century , ▁leaving ▁a ▁characteristic ▁terrain ▁of ▁hum ps ▁and ▁h ollow s . ▁ ▁A ▁notable ▁example ▁is ▁that ▁on ▁the ▁fl anks ▁of ▁C rib arth ▁explo ited ▁by ▁industrial ▁entrepr ene ur ▁John ▁Christ ie . ▁ ▁In ▁the ▁United ▁States ▁it ▁is ▁mainly ▁produced ▁in ▁Ark ansas , ▁Illinois , ▁and ▁Oklahoma . ▁ ▁See ▁also ▁ ▁Metal ▁pol ishing ▁ ▁P um ice ▁ ▁Wood ▁finishing ▁ ▁References ▁ ▁External ▁links ▁On ▁Rotten - St one ▁and ▁Em ery . ▁ ▁Pen ny ▁Magazine ▁of ▁the ▁Society ▁for ▁the ▁D iff usion ▁of ▁Use ful ▁Know ledge . ▁ ▁July ▁ 1 5 , ▁ 1 8 4 3 ▁Volume ▁ 1 2 , ▁p