How are realgar and orpiment formed in rocks?

Realgar and orpiment are always inseparable in the rocks, just like pairs of mandarin ducks, so they are nicknamed "Yuanyang Mine".

The chemical composition of orpiment is arsenic sulfide or arsenic tetrasulfide, which is orange-red, so it is called "cockscomb stone". The chemical composition of orpiment is arsenic trioxide and slightly green lemon yellow. People can distinguish between males and females according to different colors, but realgar will directly become orpiment after long-term illumination.

There is a record of realgar mine in Shan Hai Jing more than two thousand years ago. Jiepai Gou Realgar Mine in Shimen County, Hunan Province, with a reserve of 500,000 tons and a purity of over 80%, is the largest realgar mine in the world. 1September, 965, a very large realgar crystal was found there, weighing 255.32 grams. 1988 In February, this huge realgar crystal with bright red light appeared in the international exhibition of specimens and gems held in Tucson, USA, which surprised mineralogists and gem experts from all over the world.

Realgar, as a traditional Chinese medicine, has the effects of expelling wind, killing insects and detoxifying. It has a particularly pungent smell, and snakes and insects will run away quickly after smelling it. Therefore, people should carry some realgar with them when they enter the mountains to prevent the invasion of snakes, insects and wild animals. In the traditional Dragon Boat Festival in China, it is customary to drink realgar wine and sprinkle it all over the house for disinfection. However, the intake of realgar should not be excessive, otherwise it is easy to be poisoned. According to statistics, from 1975 to 1985, more than 330 people died from drinking realgar wine. Orpiment is similar to realgar in medicine. The amount of orpiment is small and the price is more expensive than realgar, so it is often used as a high-grade pigment.

Realgar is mainly used to extract arsenic to smelt alloys. Arsenic-copper alloy is used to make automobile and radar parts. Adding 0.5% arsenic to copper can greatly increase the arsenic content and make warheads. Gallium arsenide synthesized from arsenic and gallium is used to manufacture high-power semiconductor devices.