Sphalerite

Sphalerite is the major ore of zinc and often found with the mineral Galena. When it is in pure form, with little or no iron, it produces clear to translucent crystals. The colors found in this mineral will vary, the pale yellow color is known as Cleiophane. The orange and red shades are known as Ruby Blende or Ruby Jack. Specimens with high iron content form dark, opaque metallic crystals which are dark grey to black and are known as Marmatite or Black Jack. Some specimens have a red iridescence within the gray-black crystals, these are called "ruby Sphalerite." Sphalerite is also known as Blende or Zinc Blende. It makes an interesting and attractive cabinet display specimen. It can have excellent luster and enhances many other beautiful minerals.

Other Zinc Ores include Hemimorphite, Smithsonite, Willemite, Franklinite and Zincite. Although Sphalerite’s importance as a Zinc Ore is well known, it is a very attractive and definitely interesting mineral for collectors as well. Gemmy, pale specimens from Franklin, New Jersey are highly fluorescent peach-orange and/or blue under long wave ultraviolet light (LWUV) and are known as Cleiophane, an almost pure variety.

Another interesting variety of Sphalerite found in Europe (Poland or Germany) is known as Schalenblende. This is a banded variety associated with Wurtzite and often also Pyrite and Galena that forms patterned concentric shapes. It is usually cut into slabs and polished, which are very popular with collectors. Schalenblende is also fluorescent displaying a peach-orange color under long wave ultraviolet light.