Architectural moldings of rigid thermoset polymer based material

In combination, an elongated substantially rigid architectural trim molding having the appearance of being made of natural stone, Said substantially rigid molding shaped by milling of substantially rigid non-laminated thermoset polymer based material having the appearance of natural stone so as to provide said substantially rigid molding with a sculptured decorative front surface and an oppositely disposed back surface with said back surface having an elongated generally dovetail shaped groove extending the full length of said substantially rigid molding, a narrower portion of said dovetail shaped groove being positioned near said back surface, and a wider portion of said dovetail shaped groove positioned more toward said front surface of said substantially rigid molding than said narrower portion of said dovetail shaped groove, a plurality of attachment fixtures affixed to a wall with said fixtures in straight-line alignment and in spaced relationship to one another, each of said fixtures including a rigid mounting base having extending and curved flexible spring biased tabs, each of said mounting bases having at least one elongated aperture with a fastener in said aperture attaching the fixture to said wall, each of said fixtures affixed to said wall with said mounting base against said wall and said curved flexible spring biased tabs extending outward away from said wall, said curved flexible spring biased tabs of said fixtures extending into said dovetail shaped groove of said substantially rigid molding with said back surface of said substantially rigid molding against said wall, each of said fixtures sized relative to said dovetail shaped groove so as to have said curved flexible spring biased tabs under constant tension within said dovetail shaped groove and applying constant outward pressure against the rigid material of said substantially rigid molding defining said dovetail shaped groove so as to hold and draw said substantially rigid molding securely against said wall, said substantially rigid molding sized relative to said fixtures so as to obscure from view said fixtures holding said substantially rigid molding, said substantially rigid molding being substantially and sufficiently rigid so as to require substantially all deflection which occurs during an initial placement of said curved flexible spring biased tabs into said dovetail shaped groove to occur in said curved flexible spring biased tabs of said fixtures.