SIDERITE

HISTORY, NAME, LOCALITIES: Siderite, pronounced SYE-der-ite, has been known since antiquity and was recognized as mineral species in 1845.  Its name stems from the Greek sideros, meaning “iron,” alluding to its composition.  Siderite is abundant and widely distributed with notable collecting localities in Germany, England, Portugal, South Africa, Bolivia, Canada, and the United States (Colorado, Idaho, Arizona, North Carolina, and Connecticut).

MINERALOGY, PROPERTIES, OCCURRENCE: Siderite [iron carbonate, FeCO₃] crystallizes in the trigonal system, usually as rhombohedrons with curved faces; it also occurs in compact, botryoidal, fibrous, granular, and stalactitic forms.  Well-formed crystals are rare.  It is usually translucent and light-to-dark brown in color; occasionally it is reddish-brown.  It has a Mohs hardness of 3.5-4.0, perfect cleavage in three directions to form rhombohedrons, a vitreous-to-dull luster, a conchoidal fracture, and a specific gravity of 3.8-3.9.  Siderite forms in a number of mineralogical environments, including sedimentary deposits, carbonatites, and hydrothermal veins.

METAPHYSICAL PROPERTIES, LORE, USES: The first great iron deposits that fueled the early years of the European and North American iron industries were siderite oolites (granules) that were laid down on seabeds hundreds of millions of years ago.  Siderite is still a minor ore of iron in some regions today.  According to metaphysical lore, siderite is a crystal of positive energy that stimulates the development of constructive thoughts and ideas, while reinforcing interest and enthusiasm about careers and other works.

COLLECTORS’ INFORMATION: Siderite crystals are collected for their rarity and for the unusual curved faces of their rhombohedrons.

CHALCOPYRITE

HISTORY, NAME, LOCALITIES: Chalcopyrite, pronounced kal-coe-PIE-rite, has been known since antiquity and has variously served as an ore of copper, iron, and sulfur.  Its name is derived from the Greek words chalco, meaning “copper,” and pyr, “fire,” alluding to its copper content and tendency to spark when struck with iron or flint.  Chalcopyrite is abundant and widely distributed.  Notable collecting localities are found in Peru, England, Mexico, Australia, Bolivia, and the United States (Arizona, Colorado, Utah, Montana).

MINERALOGY, PROPERTIES, OCCURRENCE: Chalcopyrite [copper iron sulfide, CuFeS₂] crystallizes in the tetragonal system as sharp, distinct, equant or wedge-shaped crystals.  Chalcopyrite is opaque and has a bright metallic luster.  Its color is brass-yellow to golden yellow; oxidation creates a dark tarnish that is often iridescent with hues of green, gold, and magenta.  Chalcopyrite has a Mohs hardness of 3.5-4.0, poor cleavage in one direction, and a specific gravity of 4.1-4.3.  It occurs in many mineralogical environments and reaches its highest levels of crystal development in hydrothermal-vein deposits where it is often associated with quartz.

METAPHYSICAL PROPERTIES, LORE, USES: Medieval physicians believed that when ingested, powdered chalcopyrite alleviated the symptoms of fevers, infections, and inflammations.  According to modern metaphysical lore, chalcopyrite enhances perception, acts as a connective force in interactions with other cultures, and helps to remove energy blockages that interfere with meditation.  Chalcopyrite is a major ore of copper.

COLLECTORS’ INFORMATION:  Chalcopyrite is widely collected for its well-formed crystals, brassy-yellow color, metallic luster, and frequent associations with such other minerals as quartz.