A miniature Bronze Age axe head was handed over to the National Museum of Ireland after pictures emerged of it on social media.
The axe was discovered through illegal metal detecting in Adare, Co Limerick.
NMI Keeper of Irish Antiquities Maeve Sikora said a member of the public alerted the museum to the images and the axe was recovered following an investigation by gardaí.
Speaking on RTÉ's Morning Ireland, she said it is against the law to metal detect without a licence and metal detecting is regulated under the National Monuments Act, not only to protect objects but also the context in which they are found.
"For archaeologists, the context is really key. So while an object is important, where it is in the ground, the layers that surround it and the position it's found in, can yield an awful lot of information", she said.
She said that for example other tools and weapons from the Bronze Age can sometimes have a piece of wood in the socket and radiocarbon dating can be used to accurately date the object.
Ms Sikora said the socketed axe head dates to around 1,000BC and was probably used in woodworking.
She said there are many other elements of community archaeology to get involved in and advised against unlicensed metal detecting because of the risks involved to archaeological monuments, which are not always visible above ground, and to archaeological objects and deposits.
Ms Sikora said the case is a good example of where an object was not reported to authorities and would have been lost otherwise.
She cited a recent discovery of an arrow head by a hillwalker in Cork, who immediately reported the find to the museum and even noted the coordinates on their GPS.
Ms Sikora praised the member of the public who alerted the NMI to the Bronze Age axe, adding: "My view of it is these objects belong to everybody and the National Museum's responsibility to ensure these objects are preserved for future generations ... it's a serious matter."
Meanwhile, the little axe is undergoing conservation at the museum as there is some damage to the socket, but it is expected to go on display at a later date.
NMI Director Lynn Scarff said: "The moment artefacts of archaeological significance are taken from the ground they are under threat of deterioration and it’s also critical for our staff to study the 'find spot' because it can provide important evidence, both about the item and the area in which it was discovered.
"Therefore, it's a matter of grave concern for us that the illegal use of metal detectors to search for archaeological objects continues and we want to appeal to members of the public to consider the greater public interest and the importance of these items to our national heritage, and to report any finds of note to us.
"Thankfully this impressive axe-head was spotted on social media and a vigilant member of the public reported it appropriately. It's a great example of active and responsible citizenship, working with the authorities to protect our shared heritage."
The case is being investigated by An Garda Síochána's Arts and Antiquities Unit and a file is being prepared for the Director of Public Prosecutions.