Jewel is known as the name of an award-winning singer/songwriter or a precious gem, but JUUL, pronounced the same way, has created something much more sinister: an e-cigarette the size of a flash drive (it charges in a USB port) that’s got 14-year-olds smoking, even in school!

JUULs are the latest e-cigarette craze, and a survey by Truth Initiative found that almost 20 percent of teens reported seeing a student use a JUUL at school, even though they are only legal if you’re 18 or 21, depending on your locale.

In truth, JUULs are readily available and not just online. Three out of four kids get them by strolling into a retail outlet and putting their money down, no questions asked! The Centers for Disease Control and Prevention found that from 2016-17, sales increased 641 percent — from 2.2 million devices to 16.2 million.

Why are they so appealing? They come in flavors like mint, mango, cucumber and fruit, and that makes them sound harmless enough to many kids.

But the U.S. surgeon general says they are powerfully addictive and pose a threat to public health because they are linked to a variety of health woes, from heart disease to cancer.

So parents, go to the JUUL website and get familiar with these deceptive-looking pods; they resemble something digital that might have class assignments on them.

E-cigarettes typically won’t make clothes smell, as tobacco smoke does, so you may not know that your kids are experimenting with nicotine. And talk to your children about JUUL’s dangers. Some people believe they’re designed to convert kids to cigarettes or other standard tobacco products.

Mehmet Oz, M.D., is host of “The Dr. Oz Show,” and Mike Roizen, M.D., is Chief Wellness Officer and Chair of Wellness Institute at Cleveland Clinic. Email questions to youdocsdaily@sharecare.com.