Iron is a common component of inclusions in Quartz: in the form of oxides as Hematite or Magnetite, in the form of hydroxides as Goethite or Limonite or in the form of sulfides as Pyrite and Marcasite. The exact mineralogical distinction betwee Hematite and Goethite is represented by the presence of water in the molecule of Goethite, but in real specimens where crystals are included in quartz, this is quite difficult. Both are quite similar when they are in needle shaped crystals.
Goethite usually forms small fibers crystals, often grouped in small spray aggregates, of a golden shining yellow color. Goethite is common in Amethyst Quartz or almost ligh purple amethyst. Most of iron in clear quartz is in the form of Hematite.
The most popular variety is the sa called Super Seven Quartz, a variety supposed to contain seven minerals (Amethyst, Clear Quartz. Smoky Quartz, Cacoxenite, Rutile, Geothite and Lepidocrocite) and to "stimulating all types of psychic abilities, including telepathy, clairvoyance, clairaudience, channeling, telekinesis and others." In reality the only present inclusion resulted to be Goethite, so it would be a nice Super Two Quartz, like all the other quartz with inclusions. Despite the terrible origin of this name, it is a nice commercial name that everybody knows and for that reason easy to use.
Another form of Goethite is in the form of fracture filling film. As manganese form secondary dendrites in fractures, iron forms nice red and yellow halos in the fractures in quartz.

These are three variety of Super Seven from different deposits in Brazil.

Left: Geothite spray in Amethyst lying above a phantom. Right: Iron Oxides in the form of fracture filling film.