Why is mercury sulfide not easy to absorb?

Mercury sulfide is a solid that is extremely insoluble in water, and there are two kinds: red and black. Generally speaking, sulfides of heavy metals are insoluble in water.

Mercury sulfide has a very small solubility and cannot be dissolved under the action of hydrochloric acid and sulfuric acid, so it cannot be dissolved by gastric acid in the stomach, nor can it produce mercury ions and hydrogen sulfide, and it is harmless to take it in a small amount.