Gold Dalek

Gold Daleks, also referred to as Golden Daleks, (PROSE: Doctor Who and the Day of the Daleks) were a high-ranking class of Daleks within the Dalek Empire prior to the Last Great Time War. They were denoted by their gold casing.

Nature
Gold Daleks were the highest-ranked Daleks within the Dalek hierarchy with the exception of the Dalek Emperor or the Dalek Prime, above Grey Daleks, Blue Daleks, Red Daleks, Black Daleks (PROSE: War of the Daleks) and Silver Daleks. (TV: Death to the Daleks). The Eighth Doctor referred to them as the "elite". (PROSE: War of the Daleks) Gold Daleks could ascend to membership of the Dalek Council and, thereby, the rank of Dalek Supreme. (TV: Day of the Daleks, PROSE: Dalek: The Astounding Untold History of the Greatest Enemies of the Universe)

History
A Gold Dalek on Skaro oversaw the capture of Don Morais and Zec and tasked them with retrieving a stratum of the mineral Doranium beneath the planet's surface. (COMIC: The Dalek Trap)

However, Gold Daleks only became a major part of Dalek hierarchy some time after the end of the Dalek Civil War at the culmination of the Great War. (TV: The Evil of the Daleks, PROSE: The Evil of the Daleks)

On the eve of the Second Dalek War of the 26th century, a Gold Dalek (TV: Frontier in Space) belonging to the Supreme Council (PROSE: Dalek: The Astounding Untold History of the Greatest Enemies of the Universe) led a platoon of Daleks to meet on the Ogron homeworld. There, it ordered the Master's captives — including the Third Doctor, Jo Grant, General John Williams and the Draconian Prince — exterminated. However, the Master convinced the Daleks to leave the prisoners under his supervision until the Daleks' planned war began, to which the Daleks agreed and left the planet. (TV: Frontier in Space)

This allowed the Doctor to foil the Daleks' plans on Exxilon, (TV: Planet of the Daleks) leading the remorseful Gold Dalek to organise a large-scale time travel mission to rectify its mistake, taking control of Earth in the 22nd century. (PROSE: Dalek: The Astounding Untold History of the Greatest Enemies of the Universe) This timeline was negated by an earlier version of the Third Doctor, leading to the destruction of the Gold Dalek by Shura at the Auderly House using a Dalekanium bomb. (TV: Day of the Daleks)

Another Gold Dalek holding the rank of Dalek Supreme when the Daleks tried to launch and invasion of Earth from the planet Balbo. Its ally, Jane Davis-Hunt, called it a "gold-plated dustbin". When the Third Doctor and Sergeant Benton raided the Dalek city on Balbo, the Dalek Supreme switched to emergency static power when Skwoj's interference device cut off its main supply. Skwoj and Benton forced the Dalek on top of a plastic cape, insulating it from the floor and deactivating it. (AUDIO: Poison of the Daleks)

Following the end of the Imperial-Renegade Dalek Civil War, Dalek forces were divided as some supported Davros while others supported the Dalek Prime. The Gold Daleks were the only rank that remained fully loyal to the Dalek Prime, which gave him an advantage when a brief but destructive civil war broke out on Skaro. They were aware that their power would be diminished if Davros took over. (PROSE: War of the Daleks)

Other Gold Daleks
The early Dalek Emperor and Dalek Prime, had a distinct gold casing made of Flidor gold. (COMIC: Genesis of Evil, PROSE: The Chase, War of the Daleks) The Emperor was also referred to as the Golden Dalek. (PROSE: The Outlaw Planet)

Following the Third Doctor's escape from the captivity of the Master and the Daleks, (TV: Frontier in Space) he had the Time Lords send him to Spiridon where the Daleks were in the process of waking up an army from under the ice. There, a black Dalek Supreme with a golden dome, solar panels and globes arrived on the planet to take charge of the mission and was said by the Thals to be a member of the Supreme Council (TV: Planet of the Daleks) A similar Dalek led the force with captured various Earth naval vessels and raided Sydney Harbour. (COMIC: *Sub Zero) Another Dalek Supreme with the same casing was part of a mission on Kar-Charrat to obtain information from the planet's Library. It was the immediate subordinate to the Emperor. (AUDIO: The Genocide Machine)

By the end of the Second Dalek War, many Daleks had been given a sturdier bronze and gold casing and Dalek X, the Dalek Inquisitor General, had a black casing with golden globes and solar panels. (PROSE: Prisoner of the Daleks) Such Daleks also fought against the Movellans. (TV: The Pilot)

Davros's Imperial Daleks had white casings decorated with gold, including their globes, indicator lights, gunsticks, manipulator arms, neck casings and eyestalks. (TV: Revelation of the Daleks, Remembrance of the Daleks)

A Supreme Dalek commanded the invasion of Gallifrey. It had bronze and gold casing with black dome and globes. (AUDIO: Extermination, Ascension)

During the Last Great Time War, the bronze and gold casing from the Second Dalek War and the Movellan War became standard for Dalek drones (TV: Dalek, The Last Day, The Day of the Doctor, PROSE: Engines of War) and a similar look was used for the Emperor. (TV: The Parting of the Ways) These casings were eventually used again for the foot soldiers of the New Dalek Paradigm. (TV: Asylum of the Daleks, The Time of the Doctor, Into the Dalek, COMIC: The Dalek Project, PROSE: The Dalek Generation) The New Paradigm variant of Red Daleks were similarly laced with gold. (GAME: The Doctor and the Dalek)

The red Supreme Dalek of the New Dalek Empire had golden globes and extra gold casing. (TV: The Stolen Earth/Journey's End)

Merchandise

 * Dapol, which produced a range of toys based on the classic series of Doctor Who, released several original gold Dalek variants which did not appear on-screen.
 * W008-10 was completely gold.

Other matters

 * The Gold Dalek in The Dalek Trap, the first Gold Dalek to appear in any form, may have been intended to be the Dalek Emperor, which was also called the "Golden Dalek" elsewhere in The Dalek Outer Space Book. However, it was drawn in the shape of a standard Dalek. There is no time setting given for when The Dalek Trap takes place, or any connections to other stories, so any inconsistencies are ultimately avoided.
 * According to the non-narrative material in The Dalek Handbook, the civil war between the Dalek Emperor's guards and the Humanised Daleks (TV: The Evil of the Daleks) ended in a victory for the Emperor's forces. Afterwards, the Emperor revamped the Dalek command structure, which involved completely replacing Black Supreme Daleks and Dalek saucer commanders with Gold Dalek Commanders for a time. While the TV series does not necessarily contradict this, other stories such as the Day of the Daleks novelisation and War of the Daleks depict Gold Daleks and Black Daleks coexisting, and The Threat from Beneath, set during the Third or Fourth Doctor's era, has the Daleks led by a Black Dalek Commander without so much as a mention of a Gold Dalek.
 * The Eternal Dalek of the New Dalek Paradigm introduced in TV: Victory of the Daleks has a similar colour-scheme to the Gold Daleks since both have black globes. However, the Eternal Dalek has a solid yellow casing instead of gold.
 * Nicholas Briggs voices the Gold Dalek (and the other Daleks) in the Day of the Daleks Special Edition DVD.
 * A Gold Dalek, alongside a Black Dalek and a Red Dalek, leads the 22nd century Dalek invasion in Daleks' Invasion Earth 2150 A.D., a retelling of The Dalek Invasion of Earth starring Peter Cushing. This was the first Gold Dalek to be seen on colour film but they would not be seen on the proper series until Day of the Daleks.
 * The Gold Dalek is referred to as "the Golden Dalek" in Terrance Dicks's novelisation of Day of the Daleks.
 * The novelisation of Frontier in Space does not describe whether the lead Dalek is gold or not, simply referring to it as "a Dalek".
 * John Scott Martin operated the Gold Dalek in both Day of the Daleks and Frontier in Space episode six, being credited as "Chief Dalek" in Radio Times on both occasions.
 * Gold Daleks feature on the covers for the VHS, laserdisc and DVD releases of Day of the Daleks, the 1994 Polish cover of the novelisation, and on the cover of the box for the Eighth Doctor Big Finish audio anthology Dark Eyes 4.
 * In Chapter 8 of Engines of War, at least one member of the Eternity Circle is described as having a blue and gold casing. However, the rest of the novel describes all five members as having a blue and silver casing. This single reference to one of them having a partly-gold casing was likely an error.
 * A Gold Dalek appears in the movie Ted 2, where it fought Robbie the Robot.