Search Mineralpedia – A Mineral Photo Database and Identification Guide
Named for the Latin word helvus, which means “amber,” in reference to the mineral’s color, which is typically a golden-yellow. Helvite is an uncommon mineral that occurs in skarn, contact zones, gneiss, granite pegmatites, and granites. Localities for Helvite include in Germany, Sweden, Russia, Kyrgyzstan, Norway, Finland, the United States, Japan, and other localities. Helvite is pyroelectric and will generate a charge in response to heat application.
Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/helvine.pdf
Named for the Greek word aimatodes, meaning “bloodlike,” in reference to the mineral’s color and streak. Hematite is extremely common with thousands of localities with exceptional crystals from Switzerland, Romania, Italy, England, Norway, Brazil, South Africa, Algeria, and the United States. Hematite occurs as an accessory mineral in igneous rocks, as a sublimate in volcanic rocks, in high-temperature hydrothermal veins, a contact metamorphism product, in metamorphosed banded iron formations, as a cement in sedimentary and a constituent in oolitic iron formations, and it is abundant on weathered iron-bearing minerals.
Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/hematite.pdf
Named in reference to the mineral’s hemihedral morphology as exhibiting only half the faces required for complete crystallographic symmetry. Hemihedrite is a rare mineral that can be found only in localities in the United States in Arizona and Nevada, and an additional locality in the Esfahan Province of Iran. Hemihedrite forms from the oxidation of galena, sphalerite, and pyrite in hydrothermal lead-bearing veins.
Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/hemihedrite.pdf