Uraninite (mostly U02) is a radioactive, uranium-rich mineral and ore with a chemical composition that is largely UO2 but because of oxidation typically contains variable proportions of U3O8.  Radioactive decay of the uranium causes the mineral to contain oxides of lead and trace amounts of helium (through alpha decay).  It may also contain thorium and rare-earth elements.

Urinate is also referred to as pitchblende and is used primarily as a uranium ore, however most pitchblende is not in crystal form, finding Uraninite in crystal from like this is not common.  This piece came from Swamp Mine, Maine, which produces some excellent crystalized specimens. 

Pitchblende from Germany was used by M. Klaproth in 1789 to discover the element uranium.  Marie Curie used pitchblende, processing tons of it herself, as the source material for her isolation of radium in 1910.

Gamma spectroscopy of this sample shows U238, U235, and several daughter isotopes such as radium, thorium, lead 214 etc., in a few billion years this will just be a piece of lead. 

Using GMC600+ this sample emits 136 micro sieverts per hour of radiation, or roughly the equivalent of a dental x-ray every 5 minutes.  Don't let this alarm you, the plastic case you see blocks all of the Alpha and Beta radiation and those readings are only on contact with the mineral, observing with some air between you and the specimen brings the levels down to quite a safe range, you are fine.