Hearthstone was developed in the early 1980's by Radnor Homes of PA. The current S/D has 262 lots platted, with an average lot size of .46 AC, the current average Sale Price is $277,950. The Current Median Sale Price is $266,000. The local tax assessor has valued the total of all the properties in this S/D at more than $82,500,000. The highest sale price recorded for a post development lot, improved, is $815,000 transferred in 2011.