THE MINERAL BRASS
- Chemistry: Cu3Zn2, Copper zinc
- Class: Native Elements
- Subclass: Metallic Alloys
- Uses: Only as mineral specimens.
Brass is not an officially recognized mineral as yet, although it has been proposed. It is not the man-made brass that is under consideration, but specimens of naturally occurring crystals of a copper nickel alloy with a formula similar to what we know as brass. These specimens are also not common, but are extremely rare and have only been found in a couple of localities in Siberia, Russia. Brass could be considered an official mineral if the naturally occurring crystals prove to have a unique structure and chemistry from other copper nickel alloys. That may prove difficult or impossible and if so, brass will then be discounted as a mineral.
Brass is classified as an element dispite the fact, that in chemical reality, it is a compound. Minerals like brass are alloys with metallic bonds that are very similar to the more pure metallic elements and are thus classified as elements.
- Color is yellow to brassy yellow.
- Luster is metallic.
- Transparency: Specimens are opaque.
- Crystal System is isometric.
- Crystal Habits are limited to tiny grains.
- Cleavage is absent.
- Specific Gravity is 8.4 – 8.7 (man-made brass)
- Streak is brassy brown.
- Notable Occurrences are limited to two localities in Siberia, Russia; Tolbachik Volcano, Kamchatka and Vol’sk-Vym Ridge, Middle Timan.
- Best Field Indicator is color, locality, density and rarity.