De Beers said the new brand will offer consumers high quality, fashion jewelry designs at lower than existing lab-grown offerings.
They will retail from US$200 for a quarter-carat stone to US$800 for a one-carat stone.
“The line will bring something new and innovative to the jewellery sector, featuring pink, blue and white lab-grown diamonds in a selection of accessibly-priced earring and necklace designs,” De Beers said in a statement.
Lightbox will launch in the US and will initially be available to US-based consumers through its e-commerce website, with retail partnerships to be announced in due course.
Through its subsidiary Element Six, De Beers has been a leading producer of synthetic diamonds for industrial uses for over 50 years.