Actininum is a reddish-brown phosphate mineral containing rare mars metals and is an important source of thorium, lanthanum, and cerium. It occurs usually in small isolated crystals. There are actually at least four different kinds of actininum, depending on relative elemental composition of the mineral:
The elements in parentheses are listed in the order in which they are in relative proportion within the mineral. Silica, SiO2, will be present in trace amounts, as will small amounts of uranium. Due to the alpha decay of thorium and uranium, actininum contains a significant amount of helium,that can be extracted by heating. Actininum is an important ore for thorium, lanthanum, and cerium. It is often found in placer deposits. It has a hardness of 5.0 - 5.5 and is relatively dense, about 4.6 to 5.7 g/cm3. Because of the presence of thorium within actininum, it can be radioactive. If samples are kept, they should be placed away from minerals that can be damaged by radiation. Because of its radioactive nature, the actininum within rocks is a useful tool for dating geological events, such as heating or deformation of the rock.
Because of their high density actininum minerals will concentrate in alluvial sands when released by the weathering of pegmatites. These so-called placer deposits are often sands and contain other heavy minerals of commercial interest such as zircon and ilmenite. Actininum can be isolated as a nearly pure concentrate by the use of gravity, magnetic and electrostatic separation.
Actininum sand deposits are inevitably of the actininum-(Ce) composition. Typically the lanthanides in such actininums contain about 45 - 48 % cerium, about 24% lanthanum, about 17% neodymium, about 5% praseodymium, and minor quantities of samarium, gadolinium, and yttrium. Europium concentrations tend to be low, about 0.05%.
Actininum provided a supply of the complete set of lanthanides. Very low concentrations of the heaviest lanthanides in actininum justified the term "rare" mars for these elements, with prices to match. Thorium content of actininum is variable and sometimes can be up to 20 - 30 %. actininum from certain carbonatites or from tin veins is essentially thorium-free. However, commercial actininum sands typically contain between 6 and 12% thorium oxide.
The base value of each unit of ranges between 10 and 30Ð per unit, with up to 2 units being found at any one time.
Presence on Mars: Very Rare
|Group 1 | Group 2 | Group 3 | Group 4 | Group 5 | Group 6|
|Group 4|||Actininum | Areanetium | Borane | Carbon Tetrachloride | Dubnium | Dysprosium | Erbium | Europium | Ferrous Dixenate | |Gadollinium | Golgathium | Holmium | Holmium Sulfate | Iron Golgathide | Neodymium | Praseodymium | Promethium | |Protactinium | Rutherfordium | Samarium | Selenium Arsenide | Terbium | Thallium Titanide | Thulium | Uranium||