1.   In general, lunar rocks differ from terrestrial rocks in that the Moon contains much lower concentrations of easily vaporized elements.

2.   A precious metal belonging to the platinum group of elements, iridium is more abundant in meteorites than in terrestrial rocks.

3.   Iridium, a precious metal belonging to the platinum group of elements, is more abundant in meteorites than in terrestrial rocks.

4.   Terrestrial rocks show no evidence of hotter eruptions over the past half billion years.

5.   The terrestrial oldest rocks found so far have come from the Canadian Shield in the Northwest Territories of Canada.