One of the rarest artefacts is said to be a silver coin dubbed the 'ghost' coin
A number of rare artefacts - including a so-called 'ghost' coin - have been uncovered by archaeologists at the site of a 16th century shipwreck.
The Portuguese East Indiaman was part of explorer Vasco da Gama's Armada to India when it sank off the coast of Oman in 1503.
Researchers believe the suspected wreck of the Esmeralda is the earliest ship from Europe's Age of Discovery ever to be found and scientifically investigated, National Geographic reports.
An archaeological survey began in 2013 - 15 years after the site's initial discovery - and more than 2,800 artefacts are said to have been found since, including a bronze bell.
One of the rarest artefacts is said to be a silver coin, commissioned specifically in 1499 for trade with India.
There is said to be only one known other 'Indio' coin in the world, and has been dubbed a lost or 'ghost' coin for that reason.
The investigation was carried out by UK-based Blue Water Recoveries in co-operation with Oman's Ministry of Heritage & Culture.
Project Director David L Mearns said, "this project differs from the majority of maritime archaeology projects in that we set out to specifically find the wreck site of the Sodré ships, using a survivor's and other historical accounts, because of their very early age and the potential they held for new discoveries.
"It is extremely gratifying therefore that this strategy has paid off with such interesting revelations even though we are still at a relatively early stage in the study of the artefact assemblage," he added.