2.5 X 2 X 2 CM . I COMBINE SHIPPING : USA AND CANADA : YOU PAY SHIPPING ON THE FIRST ITEM ONLY. IT IS FREE SHIPPING FOR EVERY ADDITIONAL ITEM ! PLEASE COMMIT TO BUY AND DO NOT PAY SO I CAN SEND YOU AN INVOICE. IF YOU CANNOT DON'T WORRY, I WILL REFUND ALL EXTRA SHIPPING CHARGED! . OTHER COUNTRIES : SHIPPING CHARGE IS AROUND $ 9.99 PER 250 GRAMS .SAINT LAWRENCE COLUMBIUM AND RARE METALS MINE, OKA COMPLEX, OKA, QUÉBEC, CANADA . . The Oka complex is a carbonatite complex measuring 8 km by 3 km approximately. It is one of the larger intrusions of the Monteregian alkaline province which includes such well known intrusions as Mont Saint-Hilaire. The complex was intensely explored in the 1950s and significant deposits of niobium ( called columbium in the USA) were found. There are a number of individual localities within the complex, which were explored by a number of mining interests. Only one mine opened, it was the Saint Lawrence Columbium Mine, a large open pit mine that closed in the 1970's.