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.
Hematite is present in many shapes, the more commons are blade shaped more or less hexagonal crystals or fibrous crystals. They are usually black, but can be red if very thin. When Hematite is fibrous is difficult to distinguish from Goethite, that is more typical of Amethyst Quartz and is more often yellow colored. A nice variety of hematite inclusion is the so called Strawberry Quartz where Hematite blades give some Schiller effect and the Quartz take also the name of Sunstone Quartz.
Hematite is also in hexagonal black crystals at the center of Star Rutile Quartz.

Left and center: Hematite hexagonal blades, Minas Gerais, Brazil.
Right: hexagonal Hematite crystal at the center of a Star Rutile Quartz, Novo Horizonte, Bahia, Brazil.

Left: Quartz with Hematite crystals in both shapes, blades and needles, Minas Gerais, Brazil.
Right: the so called Fire Quartz is cut from the same rough of Pink Fire Quartz, from wich its name.

Red Hematite with intermittent grow where needles intermittently form blades.

Strawberry Quartz from Tamil, India with red lamellar Hematite.