白雲鄂博
Inner Mongolia, China
白雲鄂博位於內蒙古包頭以北,是地球上已知最大的稀土元素礦床,也是巨型的鐵–鈮–稀土礦床。對收藏者而言,它是鹼性岩礦物的著名產地——霓石、鈉閃石,以及一長串稀有的稀土與鈮礦物——但礦區准入受限,標本稀少。
The world's largest rare-earth deposit
Bayan Obo is a giant iron–niobium–rare-earth-element (Fe–Nb–REE) deposit hosted in dolomitic carbonatite and alkaline rocks on the northern margin of the North China Craton. It holds a very large share of the world's known light-rare-earth reserves and has been mined for iron ore since the 1950s, with rare earths recovered as a co-product. The deposit was first reported in 1927.
Why it matters to collectors
The alkaline-carbonatite setting produces an unusually rich suite of minerals. Bayan Obo is the type locality for a number of rare REE, niobium, and barium species, and yields well-known collector minerals including aegirine, riebeckite, arfvedsonite, fluorite, fluorapatite, magnetite, hematite, bastnäsite, and monazite. Its mineralogical diversity makes it one of the most-studied localities in China.
Availability
Bayan Obo is a strategically important, security-controlled operation, so crystallized collector specimens rarely reach the open market. Pieces with documented Bayan Obo provenance are correspondingly prized, especially sharp aegirine and the rarer REE accessory minerals.