Whether jumping in the ocean’s waves or noshing on some salty chips at a family picnic, during the dog days of summer, it’s pretty easy to appreciate this week’s #CrystaloftheWeek in celebration of International Year of Crystallography. Yes, this week we revel in the wonders of possibly the most valuable crystal in the world – so valuable that at times, it has even been used as currency! We’re talking about sodium chloride. And those not in a chemistry lab probably know it better as table salt.
Yes, sodium chloride seems to be everywhere, but that hasn’t always been the case. People have mined it and found ways to evaporate ocean water to create sea salt “farms.” And while it was the first “seasoning” to flavor bland foods, it also has been used to keep foods safe for long periods with its use in pickling, canning, curing and even drying meats and fish to prolong storage, especially prior to the invention of refrigeration. And, this practice continues today in many cultures, where it’s still customary to cook with salted cod rather than fresh fish to create certain stews and other meals.
For crystallographers, sodium chloride crystals represent the simplest crystal design: translucent and a perfect cube. And according to the Morton Salt company, salt has an estimated 14,000 specific industrial uses. “Several hundred of these are direct uses such as food seasoning, curing of animal hides or the preparation of saline solutions for intravenous injection. However, the greatest number of applications is indirect through the use of thousands of chemicals derived from a dozen or so basic chemicals produced from salt. Salt also plays important roles in the manufacture of steel, aluminum components, lubricants, rubber tires, seat covers, vinyl tops, paint removers, soap, textiles, ceramics, inks and dyes to name a few.” In fact, less than 10 percent of the salt that is manufactured is used in food.
One of the most interesting aspects of salt water is the buoyancy it brings to a swimming experience. In extreme places such as the Dead Sea or even some mineral baths like one at the Königliche Kristall -Therme am Kurpark in Schwangau, Germany, one finds it nearly impossible to sink in the briny fluid with approximately 31 percent and 12 percent salt concentrations, respectively.
Photo credit: Wikimedia Commons.