Nestled in the serene harbourside suburb of Mosman, Sydney, winner of the IDEA 2023 award for Colour, Black Diamond, is a masterpiece of transformation, where YSG Studio’s visionary use of architectural elements effortlessly met its client brief to convert a 345-square metre family home into a luxurious retreat, echoing the tranquil ambience of a boutique hotel.

Yasmine Ghoniem, director of YSG Studio, wholeheartedly embraced this vision, setting the stage for a texturally rich and colourfully playful design journey.      

“We orchestrated varying levels of ambience across three floors through distinctive floor and ceiling treatments, particularly immersing the main living area on the central floor in a dusky, dreamlike state,” explains Ghoniem.

The design brilliance of the IDEA winner Black Diamond is exemplified by the meticulous selection of colours, finishes and materials, such as glass bricks, Rosso travertine, black mosaics and Moroccan Zellige tiles.

Velvety Marmorino finishes in soothing hues grace the ceilings, immersing visitors in an environment of pure luxury. The upper-level master suite boasts a calming caramel hue, while the main living area below is enveloped in a deeper toffee shade, elegantly extending to the balcony and visually expanding the room’s spatial dimensions. Strategically placed jewel-hued glass bricks add a touch of shimmering opulence.

Goniem says: “We selected a verdant green and deep blue fabric to invigorate the generous sweep of the ivory banquette wool base now occupying the underused curved glass alcove.

“More subtly, the en suite’s lilac joinery internals reference the jacaranda trees surrounding the home, something we explored downstairs with the calming lavender L-shaped lounge and a custom marble coffee table with gentle boysenberry ripples, in addition to the deep purple chairs on the balcony.”

Entry points in Black Diamond are thoughtfully designed to nurture a sense of arrival, promising delightful surprises at every turn. A striking canary yellow light pole featuring ‘Poesia Golden Amber’ glass bricks​​ ascends from floor to ceiling, introducing a playful and visually captivating element to the reimagined staircase. As you descend the stairs, pale timber treads transition to stained ebony, marking the shift to the living area.

The living area resembles a rich underwater world, with accents of teal, smoky topaz and amethyst floating gracefully. A shimmering reef-like island bench, crafted from black mosaics and leathered marble, serves as the anchor of the space – inspiring the project’s name, Black Diamond.

Mosaic details extend to the floor, framing the glass doors and unifying the room. With dark timber floors and ceilings, the space offers a serene escape from the outside world, encouraging an inward-looking ambience.

A level down, the cellar door continues to astonish with its round tangerine Perspex windows, offering tantalising glimpses of the wine collection, while mirroring the sunset’s glow reflecting off the entrance’s glass console.

Black Diamond is a true reflection of its residents, an intimate and personal space that invites guests to experience a piece of the homeowners’ unique story.

“Our clients wanted a home that felt like a boutique hotel with lavish yet tranquil tones that were rich in substance, not excess trimmings,” reflects Ghoniem.

Photography by Anson Smart.