In the Marquette district of Michigan (Lake Superior) schistose specular ore occurs in important deposits, associated with a jasper rock, in which the ore alternates with bands of red quartzite.
The quality of ore in the two ranges differs somewhat, that mined from the Vermilion Range being a hard specular or red haematite, while that taken from the Mesabi Range, largely red haematite, is much softer and in many localities quite finely comminuted.
Volcanic activity in the neighbourhood is further shown by the quantities of pumice-stone drifted on to the south coasts of Kandavu and Viti Levu; malachite, antimony and graphite, gold in small quantities, and specular iron-sand occur.
Micaceous iron ore consists of delicate steel-grey scales of specular haematite, unctuous to the touch, used as a lubricant and also as a pigment.
The splendent surface has suggested for this mineral such names as specular iron ore, looking-glass ore, and iron glance (fer oligiste of French writers).
Ferric oxide or iron sesquioxide, Fe203, constitutes the valuable ores red haematite and specular iron; the minerals brown haematite or limonite, and gothite and also iron rust are hydrated forms. It is obtained as a steel-grey crystalline powder by igniting the oxide or any ferric salt containing a volatile acid.