5 Most Incredible Discoveries of the Week Including a monster diamond and a way to gauge brain power with raisins By Newser Editors, Newser Staff Posted Nov 21, 2015 5:08 AM CST 0 comments Comments Whoa. (Portland Communications, via Bloomberg) (Newser) – A new jolt in the java world and an antibiotic meltdown make the list: Here's How Often Happy Couples Have Sex: Couples who constantly "Netflix and chill" aren't necessarily happier. In fact, having sex once a week is just about perfect, according to a study of surveys of more than 30,000 Americans gathered over 40 years. It seems to trump another commonly used measure of life satisfaction. Science Says Keep Pouring That Coffee: Harvard researchers find regular coffee consumption not only boosts longevity—it reduces your risk of diabetes, heart disease, and suicide. Non-smokers who drink three to five cups of coffee daily are 15% less likely to die, while those who drink more than five cups have a 12% lower risk. Odd is what researchers discovered about decaf. Second-Largest Diamond in History Found: That'll be some engagement ring. The CEO of Canadian mining outfit Lucara Diamond says he's "truly at a loss for words" after his company uncovered the biggest diamond found in more than a century, now the world's second-largest. Culled from a mine in Botswana, the stone comes in at 1,111 carats and is just slightly smaller than a tennis ball. Gauging its worth is a little tricky, though. Get Ready for the 'Antibiotic Apocalypse': We're thisclose to these meds not working anymore, per researchers who've discovered bacteria in China that can defeat a so-called "last-resort" antibiotic. MCR-1 appears to be widespread among Chinese livestock and is beginning to appear in an alarming number of human infections. It may not be cause for panic, though. How to Predict Your Kid's Future Intelligence With a Raisin: Researchers claim they can predict how well an 8-year-old will do in school using nothing but a raisin and cup when the child is a toddler. The idea is to see how long the kids can hold out going for the raisin—in what "could be the simplest test of childhood aptitude ever invented." Click to read about more discoveries.