I wouldn't think it would violate any rules. It would most likely use whichever description is parsed last by the crawler and ignore the other one.
I dnt think so that anyone should use two description. Search engine looks only one so why we are trying to confuse to SE.
If you put two description meta tags in single page, then Google show your 1st description meta tags only.
I think, if you place two description meta tags on a web page then Google's spider will save first one for reference while second description meta tag will not help you. It will not violate Google's rules but it is also not a standard way of using meta description.
you can put up to 156 characters in description tag and the description tag should be unique tag for each page
Why do keep two Meta description Tags? What type of Meta Data do you want to use in the second Meta Description Tag? Do you want to introduce some new things in OnPage SEO?
Hi Friend, If we have use two meta tag description mean Google will take first description of 150 characters only, Remaining all are words will neglect by search engine, Meta tag descriptions are display, when user searches on a particular keywords, that time it shows on two lines under the title.
Google searches shows only maximum 67 character in title and 157 character in description after that ignore.