Also literally one of the ways to make a basic cheese (boil milk, add lemon, collect and strain curds from whey, add salt to taste). Can substitute vinegar for lemon.
You've never had surf & turf at a restaurant? And if you're vega(taria)?n, you've almost certainly had coconut & honey in some proceeded drink - honey is a common substitute sweetener for sugar, and processed sugar is considered bad in a subset of that community.
But what I wonder is where these things come from, and how common they are?
Surf & turf was me. And I am spectacularly ignorant of the vast variety of Indian cuisine, but I would be surprised if literal shells is a common staple. It doesn't say "calcium," it says "shells." And it shows a picture of what looks like a cluster of mussels, although it could be clams.
Nobody in the US eats shells like that, except for Blueshell crab almost exclusively in the mid-Atlantic region. There are some recipes where you cook crab whole until the shell dissolves into the soup, but in neither case is the point to eat the shells - they're just along for the ride to get to the meat. And if it's a source of the calcium that's sometimes added to some food, it'll say "calcium," it won't say where it came from.
So: you're claiming that it's common in India for people to, what... source and grind up shells and eat them? I suppose if folks are doing it to Rhino horns, that's not the weirdest thing I've heard. I think it's just more likely it's referring to shellfish.