The US Embassy described the lunar stone, collected by astronaut and geologist Harrison "Jack" Schmitt during the Apollo 17 mission, as a symbol of a joint dedication to the exploration of outer space.

The 120-gramme piece was part of a larger rock that weighed eight kilos when it was brought to Earth. It is estimated to be around 3.75 billion years old, which makes it older than 99.99% of all the rocks on Earth.

The first ever display of a lunar stone in Slovenia is the result of ten months of efforts by the US Embassy in cooperation with the US space agency NASA and the Noordung Centre, the US Embassy said in a press release on Monday.

The Vitanje-based centre will moreover receive at the end of August one of the 15 replicas of the space suit worn by Armstrong during the first walk on the Moon.

The replicas were displayed at baseball stadiums in the US in 2019 and this is the only one that will be put on display outside of the US. On loan from the Smithsonian museum, it will be in Vitanje until the start of November.

The US Embassy said that the US and Slovenia were bound by a long history of space exploration. It pointed to four astronauts of Slovenian descent, to the groundbreaking work of rocket engineer and astronautics pioneer Herman Potočnik Noordung and the participation of Slovenian engineer Anton Mavretič in the Voyager 1 and 2 projects.

US Ambassador to Slovenia Lynda Blanchard pointed to the moving of boundaries and new space discoveries as shared values that mark a lasting partnership between the US and Slovenia.

Dominik Kobold, the director of the Noordung centre, was meanwhile delighted to announce two "incredible exhibitions", including of "one of the most precious exhibits to have ever arrived in Slovenia".