Siderite

Thumbnails

Siderite crystals - click for larger pic
Large siderite crystals
Photo by Gilles Haineault
© Gilles Haineault

Siderite crystals - click for larger pic
Siderite crystals
© Doug Merson

Siderite crystals - click for larger pic
Siderite crystals
© Modris Baum

FeCO

Siderite has been found in pegmatites in crystals up to 25cm on edge. Most crystals are, however, in the 2-3mm range. It is a very common mineral at Mont Saint-Hilaire.

PHYSICAL CHARACTERISTICS:

Color varies from tan to beige or orange-yellow in smaller crystals;
brown to grayish-brown in the larger crystals.
Luster is vitreous to silky.
Diaphaneity is transparent in the smaller crystals, translucent to
opaque in the larger crystals.
Crystal System is hexagonal;
Crystal Habits include simple rhombohedra, modified rhombohedra,
flat, tabular crystals and curved aggregates.
Cleavage {101} is perfect.
Fracture is conchoidal to uneven.
Hardness is 4
Specific Gravity is approximately 3.95 g/cm
Streak is white.
Associated Minerals include aegirine, albite, anatase, astrophyllite,
calcite, chlorite group, dolomite, donnayite, fluorite, marcasite,
microcline, pyrite, pyrochlore, pyrrhotite, rhodochrosite, rutile,
sphalerite, synchysite and zircon.
Distinguishing Features: Crystal habit and color.
Origin: Named in 1845 from the Greek sideros, for iron, to reflect its
iron content.

CLASSIFICATION:

Dana System
# 14.1.1.3

Strunz Classification
# V/B.02-40

REFERENCES:
MinRec 21:338 (1990), Dana 8:435-436 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

MSH
¤¤¤

Legend