A Strange Messenger

During an expedition in Antarctica geologist Ben Brooks discovers by sheer coincidence a very strange small object. It's harder than diamond, and since it's lighter than air it floats around his lab. When searching government support for further research on this bizarre object it is confiscated, and a number of events start to happen. A famous NASA scientist disappears (murdered?) and Brooks and his assistant Sally have to go undercover with the object, hunted by a secret organization under the command of a grim US Army general. Brooks and Sally flee, but will they succeed to escape arrest by the FBI, the CIA, the US Army, the US Navy and the US Air Force when all of these armed forces join hands in the manhunt? And why poses such a small harmless object such a threat to the national security of the USA? Why does the US government commit third degree murder, burglary and larceny to take it away from them?