Glowstone

A fortress which once visited used a luminescent, gold-coloured material in various places. 2 blocks of it were present at the entrance, and the material was lining a portal to The End. (WC: Doctor Who Comes to MINECRAFT!)

Behind the scenes
Although it went unnamed in WC: Doctor Who Comes to MINECRAFT!, it was named 'Glowstone' in Minecraft, and was named in The Fan Show episode Doctor Who Minecraft.

References in invalid sources
Glowstone was a part of 'temporal Glowstone stabilisers', a component of the TARDIS. (NOTVALID: Doctor Who Minecraft)