The microscopy images of gold ore

Recently, a pack of gold ore was sent to our company. The ore need to identify gold with microscope. We try to observe with digital metallurgical microscope ME31 and stereoscopic microscope Olympus SZ61. Both were equipped with professional digital camera MD-30. With the apparatus, we can clearly find the gold grain in the ore.

Chalcopyrite, pyrite and raw gold ore are difficult to distinguish. However, there is a simple and effective method to tell apart them. Compared with pyrite, Chalcopyrite appears more yellow color and the lower hardness. While compared with raw gold ore, it is characteristic by dark green streak, brittle, and dissolved in HNO3. Scratching on the white board without glaze, the ore can be easily distinguished, based on the feature mentioned above. The golden streak means it is gold ore, and dark green means pyrite. Moreover, for its higher density, the raw gold ore feels heavier with similar volume.

Pic1 the raw gold ore

Pic2 the raw gold ore magnified 10 fold with stereoscopic microscope Olympus SZ61

Pic3 the raw gold ore magnified 50 fold with metallurgical microscope ME31

Pic4 the raw gold ore magnified with stereoscopic microscope Olympus SZ61

Pic5 the raw gold ore magnified 100 fold with metallurgical microscope ME31