meta description appears twice - where can I find meta ?

Hi
Google indicates I have meta description twice on some pages. I can see
<meta property="og:description"
<meta name="description"
with the same description indeed
It appears the meta property "og:description" is not important. Where could I delete it ?
I tried to find it in head.php but it's not there
Thanks

Hi

"og:description" is very important since it's the value facebook takes as site's description while shearing an article. Is google referring to this as an error ? What page is it showing for ?

If You wish to delete it than code is generated in /html/com_content/article/default.php and /html/com_k2/templates/default/item.php