Part of a mailing from MasterCard inviting John Kelly to sign up for a Luxury Card. Don’t look for plastic in one of these cards. (John Kelly/The Washington Post)

Despite what you may have heard, “conspicuous consumption” is not coughing violently in public. (Coughing violently in public, however, could be caused by antibiotic-resistant tuberculosis, and you should have it seen to.)

No, the kind of consumption deemed “conspicuous” is the buying of expensive things just to show off — to demonstrate that you can buy expensive things — rather than because you actually need those things.

I thought of that when I opened my mail the other day. Among the utility bills, Lands’ End catalogues and David Trone-for-Congress fliers was a solicitation for a new credit card. And not just any credit card, a luxury card.

Excuse me, Luxury Card. MasterCard capitalized it, so I will, too.

“Luxury” is a devalued concept these days. Everything is luxury: apartments, bath towels, face wash. It seems to me that if everything is luxury, nothing is.

Still, one must try to rise above the clatter, especially if one is in the marketing department of a credit card company, thus: Luxury Card, the prospectus of which came to me in a luxury envelope, printed with luxury ink on luxury paper, and held together by luxury staples.

I always thought a credit card was a pretty utilitarian thing. Really, it’s just a piece of plastic — embossed with your name and a 16-digit number — that allows you to buy stuff without cash, luxury stuff like white gold tennis bracelets and not-so-luxury stuff like corn- and callus-removing cream.

These days, you hardly ever need the physical credit card, just the credit card account, the details of which you dutifully enter into the computer while shopping online.

But where’s the luxury in that? Enter Luxury Card.

The very first Luxury Card feature touted in the brochure is “Metal Card Construction.” Forget you, plastic credit card.

There are three levels of Luxury Card membership. The Titanium Card costs $195 a year; the Black Card, $495; and the Gold Card, $995. The Titanium Card isn’t actually made of titanium, but it is a patented amalgam of brushed stainless steel and carbon. The Black Card is made of carbon and stainless steel. The Gold Card is made of 24-karat gold plate and carbon.

When it comes to what they make their cards out of, credit card companies are in an arms race. As with any arms race, this one will escalate to ridiculous heights. Soon, a credit card made of gold and carbon will be boring, passé. Bring me a credit card made of stem cells and pure light!

What benefits do Luxury Card holders get, beyond having a credit card made of the same stuff as your day-to-day flatware or hypoallergenic earrings? Well, you do get such things as cash back, double points when redeemed for airfare, “Luxury Gifts” (whatever they are; the Bang & Olufsen headphones in the brochure are “for illustrative purposes only”) and a subscription to Luxury Magazine, which covers such things as travel, yachts and technology.

Disappointingly, it seems that, unlike Luxury Card, Luxury Magazine is not made of metal. Just imagine 20 pounds of acid-etched copper shoved through your mailbox every quarter. Talk about conspicuous consumption!

One of the benefits enjoyed by Black and Gold card owners — but not those lowly, pathetic Titaniums — is complimentary entry to airport lounges around the world. But, according to the fine print, you can’t just show your Luxury Card to the attendant at a lounge. After all, that person probably doesn’t have access to gas chromatography-mass spectrometry equipment to assay the exact metallic composition of the card in your wallet. To get in, you have to show a separate Lounge Card.

The brochure doesn’t say what material the Lounge Club card is made of. It looks gray in a photo, so it could be made of great white shark skin or koala fur or brushed concrete. You know the Lounge Club card is luxury because on the front it says “Expiry Date” rather than “Expiration Date.”

I’m pretty sure “expiry” is the word Queen Elizabeth uses when she asks Prince Philip if the royal yogurt in the royal refrigerator is still good.

But you know what’s not so luxury? On the front of the Luxury Card, next to the expiration, er, expiry date, it says, “Good Thru.” Seems kind of lame that you’d pay a thousand bucks for a Luxury Card and the issuer wouldn’t even bother to spell out “through.”

Twitter: @johnkelly

For previous columns, visit washingtonpost.com/johnkelly.