When it set out to build a new mausoleum in 2007, Lakewood Cemetery Association, the nonprofit that manages the 250-acre historic cemetery near Lake Calhoun in Minneapolis, could have commissioned another dull granite box.

Instead it hired top-notch architects Joan Soranno and John Cook of HGA, told them to explore new design ideas and gave them two requirements: Respect the cemetery landscape and use only premium materials -- bronze, glass and stone.

The result: a stunning modern mausoleum that is a work of transcendent architecture. Its reception room, small chapel and light-filled burial rooms will comfort the bereaved and serve the cemetery well into the future. Its design should inspire a new generation of funerary architecture.

As part of the cemetery's Memorial Day event, the Lakewood Garden Mausoleum will be open for tours Sunday and Monday, with the architects present from noon to 3 p.m. each day.

Soranno and Cook had never designed a mausoleum. It isn't the kind of commission that comes along often. But their previous efforts -- from working with Frank Gehry on the Weisman Museum to their award-winning Bigelow Chapel at United Theological Seminary in New Brighton -- had prepared them for the task.

They collaborated on the $30 million project with landscape architects Liz Vizza and the Halvorson Design Partnership of Boston -- who had done a new Lakewood master plan in 2003 -- mausoleum consultant Tom Woodworth and M.A. Mortenson Construction.

Soranno and Cook researched the project to the hilt, winning the commission in a national competition.

"We took a tour of death," Soranno said of their visits to noted cemeteries and mausoleums nationwide.

Unlike most architects, who must juggle multiple projects and work as fast as they can, Soranno and Cook lead a studio within HGA that allows intense focus on one design. "I worked only on this project for 3 1/2 years," Soranno said.

In the work partnership, Soranno is the design genius, Cook the technical wiz. They are also married. In fact, they got married in Lakewood Chapel while the mausoleum project was underway.

That red-domed chapel, designed in 1910 by Harry Wild Jones, set a high mark for the new building. Its Byzantine-style exterior, with its rough rock and heavy geometry, and Charles Lamb's masterful mosaic interior of angels and grieving female figures, combine to create a beauty that touches the depths of grief.

Like the chapel, the new mausoleum resembles a geode; its stony exterior of rough-faced gray Cold Spring granite (two kinds, to get the right kind of sparkle) opens to a luminescent interior.

"The outer shell represents the roughness of life, the white interior represents the eternal," Soranno said.

The play of light and dark is maximized by the building's brilliant interaction with its site. Only one-third of the structure is above ground; the other two-thirds, including the rooms for crypts for caskets and niches for ashes, is burrowed into the south-facing hillside under a green roof.

"We wanted to make the building more intimate -- and wanted the landscape to dominate," Soranno said.

The rough gray building rises from its grassy pedestal like a force of nature. Into its facade is cut a white marble mosaic entry whose sweeping curves invite visitors to the recessed doors. The mosaic pattern of intersecting circles speaks of the eternal.

Inside, two huge windows capture Lakewood's beauty: An angled view of the domed chapel shows off its powerful volumes; straight on, two obelisks frame a monument.

Burial rooms awash in light

The interior of rift-sawn mahogany walls and black-and-white marble floors is dignified yet warm. The layout of angled and curving walls subtly leads visitors to the building's activity points: a reception room on the main floor -- the first such space for the busy cemetery -- and the small chapel or committal room downstairs on the garden level.

Also downstairs is the wing containing 12 serenely beautiful burial rooms. Far from cold and dark, they are washed by natural light. Rooms on the outside row overlook the cemetery's sunken garden, which HGA and Halvorson redesigned to be more serene, and feature large windows framing autumn blaze maples. On the inside row, asymmetrical cone-shaped skylights create a compelling sense of mystery.

Soranno said she learned three things in the course of designing these rooms. Never mix crypts and niches; some religions are against cremation. Provide variety for different tastes -- thus each room has a different color of onyx floor -- rose, green or honey. And there's no need to install sprinklers, since fire code considers these spaces to be storage.

The curving white mosaic motif of the entry recurs on the outside of the building's garden level and in the slit windows of the womb-like chapel. This unusual curved form shows up again in the chapel's ceiling, where its downward arc "feels like the weight of the Earth," Soranno said.

There is no science to designing a building so sublime that it comforts the grieving. Certain music cuts to that core where grief resides. At Lakewood Garden Mausoleum, architecture reaches those depths, as well.