- Chemistry: ((Mg, Fe)2SiO4)3
- Mg(F, OH)2, Magnesium Iron Silicate Fluoride Hydroxide.
- Class: Silicates
- Subclass: Nesosilicates
- Group: Humite
- Uses: Only as mineral specimens.
Humite is the namesake member of the Humite
of minerals. Members of the Humite Group are noted for having
a mixture of silicate layers and oxide layers in their structures. The
silicate layers have the same structure as olivine.
The oxide layers have the same structure as brucite.
In the case of humite, there are three consecutive olivine layers that
alternate between each brucite layer. The most common member of the Humite Group is
which has only two olivine layers between each
brucite layer. Humite is a fairly rare mineral. It is found in hydrothermal
veins and contact and regionally metamorphosed dolomitic
limestones as small prismatic crystals.
- Color is commonly yellow, but also white, brown or orange.
- Luster is vitreous.
- Transparency: Crystals are translucent.
- Crystal System: Orthorhombic; 2/m 2/m 2/m
- Crystal Habits include small prismatic to rounded crystals,
but as is most commonly the case, as embedded grains.
- Cleavage is poor in one direction, basal.
- Fracture is subconchoidal.
- Hardness is 6.
- Specific Gravity is 3.2 - 3.3
- Streak is white.
- Associated Minerals include magnetite,
- Notable Occurrences are include Monte Somma, Mount Vesuvius,
Italy; Paragas, Finland; Varmland, Sweden; Tilly Foster Mine, Brewster,
New York, USA and some other localities.
- Best Field Indicators are color, associations, environment of
formation and hardness.