This is a file from the Wikimedia Commons

File:Millerite in geode (Hall's Gap, Kentucky, USA).jpg

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

Original file(2,872 × 2,593 pixels, file size: 3.48 MB, MIME type: image/jpeg)



Millerite in a geode from Kentucky, USA.

A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 4900 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.

The sulfide minerals contain one or more sulfide anions (S-2). The sulfides are usually considered together with the arsenide minerals, the sulfarsenide minerals, and the telluride minerals. Many sulfides are economically significant, as they occur commonly in ores. The metals that combine with S-2 are mainly Fe, Cu, Ni, Ag, etc. Most sulfides have a metallic luster, are moderately soft, and are noticeably heavy for their size. These minerals will not form in the presence of free oxygen. Under an oxygen-rich atmosphere, sulfide minerals tend to chemically weather to various oxide and hydroxide minerals.

Millerite is an odd, scarce nickel sulfide mineral (NiS). It tends to form radiating clusters or tufts of long, hairlike needles. Some geodes in the Mississippian limestone outcrop belts of America’s Upper Mississippi Valley & Ohio Valley have millerite inside. Millerite crystals are very slender hexagonal needles with a metallic luster and a brassy-gold color.

Locality: Hall's Gap, central Lincoln County, central Kentucky, USA

Photo gallery of millerite:
Source Millerite in geode (Hall's Gap, Kentucky, USA) 2
Author James St. John


w:en:Creative Commons
This file is licensed under the Creative Commons Attribution 2.0 Generic license.
You are free:
  • to share – to copy, distribute and transmit the work
  • to remix – to adapt the work
Under the following conditions:
  • attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.

Checked copyright icon.svg This image was originally posted to Flickr by jsj1771 at It was reviewed on by FlickreviewR and was confirmed to be licensed under the terms of the cc-by-2.0.


Add a one-line explanation of what this file represents

Items portrayed in this file


3 May 2012

File history

Click on a date/time to view the file as it appeared at that time.

current05:18, 24 June 2015Thumbnail for version as of 05:18, 24 June 20152,872 × 2,593 (3.48 MB)TillmanTransferred from Flickr via Flickr2Commons
The following pages on the English Wikipedia use this file (pages on other projects are not listed):

Global file usage

The following other wikis use this file: