Local basalt stone mixed into the concrete used to construct this holiday home in India helps to connect it with its mountainous site (+ slideshow).

Mumbai firm SPASM Design Architects took its cue from the dark tones of the basalt which surrounds the site on a rocky hillside in the Maharashtra region.

"We chose to build the house as an accretion on this rocky basalt outcrop with the same inherent material transformed," the architects said, explaining how they mixed water, sand, cement and granular basalt to cast the thick raw walls.

The use of robust concrete for the Khopoli House was dictated by the drastic climatic changes that the region experiences, which include high temperatures in the summer and heavy rainfall during the monsoon season, while natural stone was used for key details like flooring.

"Stone has been used in many forms, based on use, wear, grip, texture," said the architects. "The dark, saturated black matt-ness conjures a cool sense of refuge and calm."

The house perches on the edge of a cliff with views of the distant hills, which are framed by the walls on either side of a vertiginous projecting swimming pool.

A cantilevered concrete overhang marks the entrance to the house and creates a sheltered outdoor space with a suspended sofa.

The living and dining area is located in a void between the building's two wings, with blinds enabling this space to be closed off when required.

The entrance hall and dark passages give the interior an intimate feel, while a stone-lined staircase leads to a guest bedroom and bathroom buried in the rocky hillside.

Other architectural projects that celebrate stone include an apartment block in Iran made from offcuts from a local stonecutting business and a house in England with a sliding stone wall.

Mumbai practice WE Design Studio has designed a coastal holiday home built on top of a basalt stone retaining wall with views of the Arabian Sea, while another Mumbai practice, Rajiv Saini + Associates, has created a single-storey house with a scooping cantilevered concrete roof.

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Here's some more information from the architects:

The house cast in liquid stone

A second home on a rocky outcrop at the start of the western ghats (highlands), Khopoli, in Maharashtra, India. An area of high precipitation in the monsoons, and equal heat during the summers, the site changes remarkably from March to July, with the onset of the south westerly monsoons.

Basalt the local black rock of the region is what this site was about. We chose to build the house as an accretion on this rocky basalt outcrop with the same inherent material transformed. An outgrowth which was made of a mix of water, sand, cement and the granular basalt. Concrete finely honed to serve as refuge, to face the climatic changes that the site offered.

The house was conceived as a cast for human occupation, a refuge which trapped the views, the sun, the rain, the air, and became one with the cliff edge it stood on. Akin to the growth of a coral, the substance of the walls and roof dictate the experience of inhabiting the site.

Stone has been used in many forms, based on use, wear, grip, texture. The dark, saturated black matt-ness conjures a cool sense of refuge and calm.

Photographs cannot express the sense of weight when one approaches, or the sense of release at the edge of the pool at the far end of the open terrace, the feeling of burrowing deeper enroute, past the stacked stones, to the lower bedroom.

The house, a cast, an object for living, whatever you may call it, has transformed into a belvedere to minutely observe and sense the spectacle of nature, of shade as a retreat against the sharp tropical sun, the resurgence of life, a sudden BURST of green, when the hard pounding monsoon arrives, the waft of breezes filling the air with the fragrance of moist earth, the movement of stars across the very dark night skies.

To heighten the drama of the the site through what we build, without building a dramatic building!

Lead Architects: SPASM Design Architects
Design Team: Sangeeta Merchant, Mansoor Kudalkar, Gauri Satam, Lekha Gupta, Sanjeev Panjabi
Location: Khopoli, Maharashtra, India.
Contractors: IMPEX Engineers, Mumbai
Engineers: Rajeev Shah & Associates (structural)
Site Area: 19,950 sq.mts.
Total Built Area: 638 sq.mts.
Design Period: November 2009 – Oct 2010
Construction Period: May 2011 – May 2013
Photographs: Sebastian Zachariah, Denver, Tanmay, Gauri