Most cesium is retrieved from the mineral pollucite.    From Wordnik.com.  [Cesium] Reference

Most rubidium is retrieved from the minerals lepidolite (a mica mineral) and pollucite.    From Wordnik.com.  [Rubidium] Reference

However, there are a number of minerals that contain significant amounts of cesium, including mica, beryl, feldspar, petalite, and pollucite.    From Wordnik.com.  [Cesium] Reference

These include the cesium - and potassium-rich zeolites, pollucite and leucite, and the lithium-rich mica, zinnwaldite (a variety of the mineral lepidolite).    From Wordnik.com.  [Rubidium] Reference

It is occurs several minerals such as lepidolite, pollucite, amazonite.    From Wordnik.com.  [CreationWiki - Recent changes [en]] Reference

In there, it is assumed to contain 350,000 metric tons of pollucite ore.    From Wordnik.com.  [CreationWiki - Recent changes [en]] Reference

It is occurs several minerals such as lepidolite, pollucite, amazonite, etc.    From Wordnik.com.  [CreationWiki - Recent changes [en]] Reference