The Ancient Clock is a special moving clock item that can only be obtained by following specific steps. It is locked inside the Ancient Treasure Chest, and is used to work the Time-Machine (WIP). It is somewhat similar to the Ancient Key. It is the second item in the mod with a moving texture, the first being the Dominican Amber.
It was added in the 7.2 'Ancient Kings' Build.
It is a strange golden clock that has several rings around it. When held, it does not tell the proper time, unlike a normal minecraft clock. If the player is within 3 blocks of the clock, the rings around it will start spinning, and the clock will turn to face the player.
To obtain the Ancient Clock, one must first travel to Anu's Castle, bringing all items required to defeat Anu, and find the mysterious sarcophagus in the arena and place a scarab gem in its chest. This will release Anu. After you have defeated him he will be laying on the ground with smoke coming off of his chest and will drop an Ancient Key. Grab the key and right click on Anu; you will be taken to a strange room with an ancient chest and a portal. Right click the chest with the ancient key and after a short animation, out of the chest will pop an Ancient Clock.
Place into a Time Machine. It will load up a timer, until the gui shows up. Currently, that is in the 7.3.2 build, the Ancient Clock in the Time Machine does nothing except print the words "Coming Soon" inside the Time Machine.