Copper sulfate is a chemical compound which is produced commercially by reacting various copper(II) compounds with sulfuric acid. This compound is used in a wide range of industries, from pyrotechnics to viticulture. It is also known as bluestone or blue vitriol, although these terms are not as widely used as they once were. Some caution is required in handling copper sulfate, as it is toxic and acidic, and it can pose health risks to living organisms.

The appearance of this compound varies. Generally it appears in a crystalline form which is bright blue to green; one common form of copper sulfate is the mineral chalcanthite, which appears in many arid regions of the world. Many commercial producers powder their copper sulfate before sale, making it easier to handle and to mix with other materials to create desired chemical compounds. As a general rule, copper sulfate is highly soluble, dissolving readily in a wide range of materials.

In pyrotechnics, copper sulfate is used to create striking blue fireworks. It is also used in agriculture as a treatment for crops and water systems, as it is a fungicide, herbicide, and pesticide. This compound is commonly sprayed on grapes in the form of a water solution to reduce the risk of fungal infestations. Copper sulfate is also used to treat leather, to make germicides, and in electroplating processes. It has also been historically used to dye textiles.

The use of copper sulfate in agriculture is very widespread, but it requires meticulous attention. This substance can be toxic if it accumulates in bodies of water, requiring farmers to be careful about how they apply it. When used in water treatment to remove unwanted algae and other organisms, copper sulfate is typically used in trace amounts, and the water may be filtered or treated to remove the copper sulfate before being released.

This compound is also used in chemistry. Many chemistry sets include copper sulfate for the purpose of undertaking various experiments, and the material is also used in some medical labs for diagnostic testing. When a chemistry set does include copper sulfate, it is a good idea to supervise younger users, as this substance can be potentially dangerous.

Containers of copper sulfate and products which contain copper sulfate are typically clearly labeled to indicate the fact that they contain a toxin. All hazard recommendations on such packages should be followed, including the use of skin and eye protection around copper sulfate, to ensure that you do not experience ill effects as a result of working with this common chemical compound.