The colourful and vibrant pattern has been designed in memory of Sara Pilkington who died suddenly from a heart-related condition in February 2012.
Gaye Kirby, from Durham Cathedral said: "The piece seeks to capture Sara's vibrant personality, her passion for learning and the special place that she held in her heart for Durham Cathedral.
"Seeing the window being installed is the culmination of many years of planning and we look forward to sharing the beauty of Mel's artwork with our visitors in the coming weeks and months."
Funded by Sara's parents, Jonathan and Jools, the 'Illumination Window' has been created by West Sussex-based artist Mel Howse.
Mel said: "The installation process is in itself a beautiful one, as we begin to marry the glasswork with the golden sandstone walls of Durham Cathedral.
"You can imagine the intricacy of the work involved and the immense care that needs to be taken when embedding a 26-square-metre window into such a historical foundation, but it is a challenge that my team face with enthusiasm.
"Whilst the process is ongoing, Sara is at the forefront of my mind, as the driving force behind this entire project."
The artwork, which is being installed in the north side of the cathedral, uses glass imported from Germany.
The design of the window is intended to be left open to individual interpretation.
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