OCR Text |
Show 53 With local exceptions only two vanadium-bearing minerals, carnotite and roscoelite, have been important in Southwestern Colorado. Carnotite (Kg0.2U0 .V 0 .nH 0) was the important ore mineral when radium was being produced from about 1914 to 1920 and the term "carnotite ore," established during this early period of activity, is now used for the vanadium ore, even though the mineral is not the important source of vanadium. Carnotite is a bright-yellow mineral easy to recognize; in varying quantities it is found almost coextensive with vanadium mineralization. The principal source of vanadium is a fine-grained micaceous mineral known as "roscoelite."-* This mineral occurs in exceedingly fine dark-greeniah flakes in the spaces between the sand grains. Where the spaces are only partly filled, the sandstone is gray and Is low-grade ore, but if the spaces are completely filled, it is almost black to greenish-black and is good ore. Other associated vanadium minerals that are common In the vanadium deposits follow: Vanoxite (2V 0 .V 0 .8H 0) is black mineral that is 2 4 c- o a an important ore mineral in the Joe Dandy mine in Montrose County. ^Fischer states, "....as a result of recent X-ray studies ....it is now thought to belong to the imperfectly understood hydrous-mica group of clay minerals. Even though the question of Identity is well founded the term "T-oacoellte" Is used because this is more convenient than ^=ss^x"^™.3e a new name. |