Pretzel salt is a coarse large-grained white salt of uniform size with no additives. The grains are rectangular shaped and flat. This ensures that they adhere to pretzels and other baked goods like bagels, focaccia, bread or hard rolls. The salt can also be used in coarse rubs, for curing meat, for salt crusted fish, pickling and for zucchini fritters.
Pretzel salt is also described non-melting. (King Arthur)
A distinctive feature of Rock-Pretzel Salt is that it has a translucent appearance (Morton Salt)
Pretzel salt is also known as coarse food grade salt.
Common substitutes for pretzel salt include: bagel salt, kosher salt, Red Diamond sea salt, rock salt, and Coarse Mediterranean Sea Salt.
Where to buy it. you can buy it online at Amazon and other independent sellers. it can also be bought in supermarkets like Walmart.