The term curing salts usually refers to salt with sodium nitrite, sodium nitrate, and/or potassium nitrate (saltpeter). These are commonly known as tinted curing mixture (or TCM for short), tinted cure, pink salt, sel rose, Insta Cure, or Prague Powder. You can make your own curing salts by combining natural sea salt with saltpeter, but this requires a good deal of precision and a high level of fluency with the curing process itself.
Unrefined salt is also important for curing. There are natural, albeit very low, levels of nitrate in unrefined salt that subtly help with the cure, as will magnesium and other minerals.
See our fullfull guide of curing with salt.