decay products at atomic weights below 45Sc are calcium isotopes and the primary products from higher atomic weights are titanium isotopes. Occurrence In Earth's crust, scandium is not rare. Estimates vary from 18 to 25 ppm, which is comparable to the abundance of cobalt (20–30 ppm). Scandium is only the 50th most common element on Earth (35th most abundant in the crust), but it is the 23rd most common element in the Sun. However, scandium is distributed sparsely and occurs in trace amounts in many minerals. Rare minerals from Scandinavia and Madagascar such as thortveitite, euxenite, and gadolinite are the only known concentrated sources of this element. Thortveitite can contain up to 45% of scandium in the form of scandium oxide. The stable form of scandium is created in supernovas via the r-process. Also, scandium is created by cosmic ray spallation of the more abundant iron nuclei. 28Si + 17n → 45Sc (r-process) 56Fe + p → 45Sc + 11C + n (cosmic ray spallation) Production The world production of scandium is in the order of 15–20 tonnes per year, in the form of scandium oxide. The demand is about 50% higher, and both the production and demand keep increasing. In 2003, only three mines produced scandium: the uranium and iron mines in Zhovti Vody in Ukraine, the rare-earth mines in Bayan Obo, China, and the apatite mines in the Kola peninsula, Russia. Since then many other countries have built scandium-producing facilities, including 5 tonnes/year (7.5 tonnes/year ) by Nickel Asia Corporation and Sumitomo Metal Mining in the Philippines. In the United States, NioCorp Development hopes to raise $1 billion toward opening a niobium mine at its Elk Creek site in southeast Nebraska, which may be able to produce as much as 95 tonnes of scandium oxide annually. In each case, scandium is a byproduct of the extraction of other elements and is sold as scandium oxide. To produce metallic scandium, the oxide is converted to scandium fluoride and then reduced with metallic calcium. Madagascar and the Iveland-Evje region in Norway have the only deposits of minerals with high scandium content, thortveitite ), but these are not being exploited. The mineral kolbeckite has a very high scandium content but is not available in any larger deposits. The absence of reliable, secure, stable, long-term production has limited the commercial applications of scandium. Despite this low level of use, scandium offers significant