Sustained high value is a good sales argument, longevity, on the other hand, puts stone out of reach for private buyers.
http://www.stone-ideas.com/2016/02/27/vituperation-1-emphasizing-the-high-financial-value-of-natural-stone-for-the-buyer/
http://www.stone-ideas.com/2016/02/27/vituperation-1-emphasizing-the-high-financial-value-of-natural-stone-for-the-buyer/