The architect explained natural stone was the obvious option for the home’s design, as he always turns to it when selecting material for a project. “Natural stone is consistently used as a primary finish material in my architectural projects,” he said. “Stone can be sourced locally — sometimes from the immediate site. More commonly, for a wide range of colors, finishes, sizes and costs, stone is abundantly available through international suppliers. Natural stone offers an extensive finish palette, durability, timelessness and an ecologically responsible product.”

A striking focal point of the residence is the main entry — often referred to as the “Jewel Box.” Fossil Creek flagstone from northern Arizona was chosen for this center attraction of the design. The 2- x 2-foot gridded flagstone pieces are complemented by Corton Beige limestone, which was quarried in Egypt, and used as flooring and vertical accents. Fossil Creek flagstone was also employed for interior galleries and fireplaces. The stone was all supplied by Picasso Tile and Stoneworks in Tempe, AZ.

“The color of the limestone is similar to the flagstone, but the texture of the limestone is much smoother and more consistent to create a contrast,” explained Bernhard. “The limestone is also 2 by 2 feet. The design was established to maintain full 2-foot-square sizes throughout, and joints were aligned both vertically and horizontally. In addition to these widely used stone installations, an extensive range of exotic granites and marbles were used for vanities, countertops and art niches.

“A general palette of finishes was presented to the client that included all of the proposed colors and textures,” the architect went on to say. “From this, alternate stone selections were explored — each with varying challenges and opportunities, including availability, size, consistency, cost, etc.  With guidance from the design team and builder, the client made the final selections from the range of alternate materials presented. We needed the material to be available in a fairly large quantity, and we needed thicknesses that were not typical. This directed us toward a regionally quarried material that had all of the design features we were searching for.”

In Bernhard’s opinion, stone thickness and corner or edge detailing has a strong influence on the impression of installation quality and material integrity. “Mock-ups were prepared to explore several alternatives, ranging from a thick lap to a tight quirk miter,” he said. “A blind miter was selected for the limestone, providing the appearance of thick, solid blocks of stone. A quirk miter was ultimately selected for the flagstone to accommodate the irregular cleft finish surface.

“I’ve always been influenced by the warm color transmitted through back-lit onyx,” said the architect. “This feature was designed into the entry of the home as a skylight installation. Large panels of white onyx were installed to span the area above the entry, between two adjacent roofs, creating a naturally lit arrival that leaves an impression of outdoor space.  

“To reinforce this outdoor impression, the entry was designed to represent a gateway into a mountain courtyard,” Bernhard continued to explain. “The horizontal mahogany panels and laminated glass door, and side-lite design, provide a representation of the gateway, and the large, narrow, operable, glass panels opposite the entry door provide the impression of entering into the adjacent mountain courtyard.” 

The onyx skylight was designed with integral lighting to provide warm-colored lighting at night, as well. “Mock-ups for a range of light sources were explored to achieve the color most representing day light and taking advantage of the qualities and features emitted through the backlit stone,” said the architect, who explained the process became a “co-design” effort, providing the owners with design equity. “Based on the reaction during the evolution of the home and on moving day, I believe the owners were not only pleased with the outcome, but also proud of the accomplishment that they participated in.”