Here is the website of Klaus Dona : http://www.unsolved-mysteries.info/
Includes many images.
I made it to chapter two, where I found this statement:
Nomoli figure with metal ball and “Skystones”
At 17000 years, this unusual Nomoli figure is also the oldest. A small metal ball was hidden in a hollow space inside it. An analysis showed that it is made from chrome and steel. However, the metal ball was already in the figure when it was found. How did it get there? And much more important - where did the metal come from? - The blue “Skystones” are another mystery. A legend says: The part of the sky in which the Nomoli lived turned to stone. It splintered and fell to Earth as pieces of rock. Scientists found traces of iridium in the “Skystones”. However, there is no iridium on Earth, unless it was brought in from space by a meteorite.
Iridium is a rare earth mineral. It may have originally found its way here from some past meteorite impact, or not, but the statement that "there is no iridium on earth, unless it was brought in from space by a meteorite" is indicative of someone who has not performed due diligence.
Here is the opinion of orthodox science - from wiki:
The unusually high abundance of iridium in the clay layer at the K–T geologic boundary gave rise to the Alvarez hypothesis that the impact of a massive extraterrestrial object caused the extinction of dinosaurs and many other species 65 million years ago. Iridium is found in meteorites with an abundance much higher than its average abundance in the Earth's crust. It is thought that the total amount of iridium in the planet Earth is much higher than that observed in crustal rocks, but as with other platinum group metals, the high density and tendency of iridium to bond with iron caused most iridium to descend below the crust when the planet was young and still molten.
These are all hypothetical opinions. They do not preclude the possibility that iridium has been here all along, albeit in minuscule quantities. Dona has assembled an impressive collection of photos of "mysterious" ancient artifacts, though.