Dwarf star alloy
Dwarf star alloy was an alloy obtained from white dwarf stars. It was very expensive and very heavy. It was impregnable to any form of particle (DW: Day of the Moon) and was the only material that could hold time sensitive species. (DW: Warriors' Gate)
Rorvik's spaceship was made from dwarf star alloy and required very large engines in order to achieve flight. (DW: Warriors' Gate)
Cadwell had a gun that fired pieces of dwarf star alloy. (PDA: Fear of the Dark)
Roz Forrester used dwarf star alloy to crush an N-Form. (NA: So Vile a Sin)
Father Kreiner had a glove made of dwarf star alloy. (EDA: Interference - Book Two)
Father of Mine was constrained with a chain made from dwarf star alloy. (DW: The Family of Blood)
The United States of America military constructed a cell of dwarf star alloy in which to hold the Eleventh Doctor, to which he stated that it would still not be enough to contain him. (DW: Day of the Moon)