Great keyword. But this has two problems...
1. Too generic
There is such a thing. Generic terms such as Insurance or Music are great because they have meaning while unaccompanied. Marble, however, is almost always accompanied by a keyword - whether it's marble flooring, marble countertops, or marble backsplashes. Building a site around all marble related products would be quite difficult given the many possible meanings, as well as the nature of the product as I describe in point
#2.
2. Product is not sold online
Marble is heavy and requires much machinery to customize, and the process one must undertake to install it is quite strenuous. For that reason, it cannot be sold online like an MP3 player or a pair of shoes could.
This is the exact reason as to why I felt as though Guns.com shouldn't have gone for $800,000. Given the licensing requirements in most states for the purchase of firearms, one would not be able to purchase one online, so the most purpose the site could serve is a review site or a news site.
I agree with Melly... this is probably a $xxx name for a reseller... but you'll have a difficult time finding an end user. Contacting contractors directly wont be easy as contractors with websites are in the minority, and I've tried selling different products to contractors before... it's not easy, and when they are faced with a solicitation, it's not always pretty.
Just my $0.02.