Prospecting Guide - Platinum Group Elements
Prospecting for platinum group elements can offer some similarities to prospecting for Gold. This is due to the fact that some of these elements form in placer deposits along with gold. The same methods of prospecting for placer gold such as panning and metal detecting can be used for platinum placers.
Not all of the minerals in the platinum group offer this advantage however. Below you will find a detailed description of each mineral in the platinum group, along with occurrence information for each. There are currently no placer gold claims in New Brunswick which offer placer platinum as well, but that's for us to discover.
Platinum - Platinum as a native element is relatively rare, although it does occur in placer deposits around the world. The Most common ore mineral of platinum is Sperrylite which is actually an arsenide mineral contained within the pyrite group. Sperrylite itself is particularly resistant to weathering and can be found in alluvial deposits of streams. Due to this fact, stream sediment sampling is often a successful way to prospect for this mineral. Minor anomalies can be indicative of a deposit in rock near by.
Furthermore the geological setting of Platinum is usually confined to Ultramafic rocks or layered complexes. Sometimes platinum can be found in sedimentary rocks, however economical amounts are not common. These deposits are typically associated with gold bearing sediments as well and have undergone several geological processes to reconcentrate the elements in it's host rock. More information on Platinum can be found in our blog by searching keywords such as "Placer Platinum" and "Platinum Exploration"
Above - Sperrylite (A major ore of Platinum)
Below - A piece of Native Iridium
Osmium - Osmium is one of the worlds least abundant minerals. It is often found in sulfide minerals associated with platinum, iridium and other platinum group elements. One of the most common occurrences of osmium is associated with the mineral Osmiridium, which is an Osmium - iridium alloy. This particular mineral is usually more enriched in Osmium than iridium. Osmium is found most abundant in three geological settings, Igneous Intrusions, Ancient impact craters and either of the previously mentioned which have been reworked by geological processes. Osmium is also found in small amounts alloyed with Copper and Nickle minerals. This type of alloy is characteristic of all platinum group elements.
Iridium - Is another rare element in the platinum group. Gold is on average 40 times more abundant than Iridium and Platinum around 10 times more abundant. Given this minerals love of iron, it is thought that iridium is probably more concentrated closer to the earths mantle where higher concentrations of iron are found. Iridium is found in similar geological structures to Osmium and other platinum group metals. Given the lack of major deposits of this mineral Iridium is typically mined as a by product metal in Nickle, Iron, Platinum, Copper deposits