Tuesday, December 2, 2008

Main Types of Gold-Bearing Ore Material (Part 1)

Listed below are the the first 5 of the 10 main types of gold-bearing ore material:

1. Antimony Sulphide Ores: Gold can be associated with antimonite (chemical designation: Sb2S3), an antimony sulphide mineral that is dull grey in appearance, streaks black, and is quite soft (a 2 on the Mohs harness scale). Noteworthy deposits of antimonite gold ores have been found in California, Nevada, Idaho, and Alaska.

2. Arsenic Sulphide Ores: Most commonly known as the mineral realgar (chemical designation: AsS, with As4S4 rings), arsenic sulphide ores are well known to gold prospectors due to their orange-to-bright red coloration and frequent association with precious metals. Realgar-based gold ores have been found throughout the American West, with significant deposits occurring in the state of Utah.

3. Carbonaceous Ores: These types of gold ores are sometimes called thucholite ores (chemical components: Th, U, C, H, O) and have been found in extensive gold deposits in South Africa and at the Carlin, Nevada mines. Thucholite ores are often difficult to process and require significant amounts of pre-treatment due their high iron content.

4. Copper Sulphide Ores: Also known as chalcocite (chemical designation: Cu2S), copper sulphide ores are mainly found in what are termed "supergene mineral enrichment zones." Chalcocite deposits have been mined since recorded history for their high copper content (often as much as 80%) and the additional bonus of the gold they carry (20%-40%). These ores tend to be dark grey or black in color, streak gray or black, and are associated with quartz, chalcopyrite, azurite, and many other minerals.

5. Free-Milling Ores: These types of ores are the most common and the most easily recognized of all the gold ores. A good example would be "sugar" quartz shot through with metallic gold, not unlike the photographic example at the beginning of this post. Free-milling gold ores get their name from the simple fact that they can be easily crushed, washed, and milled to recover the gold contained within them.

In my next post on this subject, I will discuss the last five types of gold-bearing ore material. Until then be safe.

(c)  Jim Rocha (J.R.)  2008


  1. This site was no help

  2. Thanks for commenting. Your view is appreciated but not shared by most other readers. J.R.

  3. Just reading through some old post, ignore him I love this site as do may others I am sure of it.
    Thanks Brandon

  4. Thanks for your support Brandon. Like everything in this life, ya gotta be ready to take the bad along with the good. Keep coming back my friend! Jim (J.R.)

  5. hey JR its me "Lost Doukhobor Ledge" and yea agree with Brandon this sight and your knowledge is helping me alot. Thanks!

  6. Thanks. I'm glad that the site and my work on it is of help. Best of luck! Jim (J.R.)