Holmium (Ho) is contained in the following rare earth mineral:
Along with dysprosium, holmium has incredible magnetic properties. In fact, some of the strongest artificially created magnetic fields are the result of magnetic flux concentrators made with holmium alloys. In addition to providing coloring to cubic zirconia and glass, holmium can be used in nuclear control rods and microwave equipment.
References
https://en.wikipedia.org
https://excelchemistry.wikispaces.com/Holmium