This piece of amber weighing 50.4kg, the world's largest, belongs to a Singapore businessman who wants to be known only as Mr Joseph. Formed in the Miocene era more than 15 million years ago, it was found early this year in a coal mine in Sumatra, Indonesia. This piece of amber reflects blue light under an ultraviolet light source (torch on right), and reddish-brown light under a daylight light source (torch on left). The owner would reveal only that the piece of amber cost him a six-figure sum in Singapore dollars. While wishing to remain anonymous, Mr Joseph is happy for people who are interested in the piece to view it. Those keen to do so may send an e-mail to firstname.lastname@example.org to make an appointment. This piece of amber is pending ratification from the Guinness Book of Records as the world's largest. The current Guinness record for the largest piece of amber is 47.5kg, held by a museum in Copenhagen, Denmark.