Ontario Mineral - Geothite

 

Rocks Minerals Ontario Geothite
Chemistry:
 FeO(OH), Hydrated Iron Oxide
Class:
 Oxides and Hydroxides
Subclass:
  
Group:
 Goethite
Uses:
 important ore of iron, pigment
Color:
 yellow, brown, brownish red to black. Sometimes tarnished with irridescent colors
Luster:
 earthy to dull for massive forms and metallic for crystals.
Transparency:
 crystals are opaque
Crystal System:
 orthorhombic; 2/m 2/m 2/m
Crystal Habits:
 include prismatic and platy crystals, massive and aggregate forms include internally radiating or fibrous; reniform, botryoidal and stalactitic.
Cleavage:
perfect in one direction.
Fracture:
 uneven to splintery
Hardness:
 5 - 5.5
Specific Gravity:
 variable at 3.3 to 4.3 (light for metallic minerals)
Streak
 brown, brownish yellow to orange yellow
Other Characteristics:
  
Associated Minerals:
 include a large list of minerals (particularly secondary deposit minerals).
Local Occurance:
 Fluor-richterite Occurrence, Saranac Mine
Best Field Indicators:
 crystal habit, streak and tarnish

Description:

Goethite has had a reputation for making rather uninteresting, dull and "dirty" mineral specimens. This is definitely not true of many of the fine specimens available to collectors today. Some good pieces show splendid radiating clusters of deep black crystals. Massive stalactitic forms show rainbows of irridescent colors on surreal landscapes. Many times Goethite forms the backdrop or matrix for other minerals such as red Vanadinite, making a visually appealing mineral specimen.