NFC Mifare Classic Tag Not Detected by Reader but Other Tags Work Fine

I am writing about a problem with my NFC type mifare classic, the NFC tag that I have seems damaged because it is not recognized by the nfc reader and with other NFC tags if it recognizes them. If you had any experience similar to this case, I would like you to share some advice, maybe it is me who is not following some kind of care in storing them.

Cristian, you can get NFC reader apps for Android phones (not older Apple phones, not sure about the newer ones).  I will try to find the name of the one I had (changed phones since then) and let you know.  At the least, it would confirm if your tag is dead, but tags are cheap and I'm sure you can get another one.  You may have ID cards with NFC chips in them, they often work as well.I would not worry too much about this, the tags / cards don't last for ever and they get a fair bit of physical handling (bending etc).  I've always been amazed they last as long as they do.
Cheers // David

Cristian.... some time ago Elektor Magazine enclosed an NFC card with their issue (Jan 2016) and you could read it and use the result to enter a competition.  I won a pair of ST boards, a reader and a programmable tag.  I did play with them a bit at the time and should do so again.    But here is a link to the android reader from ST:
https://play.google.com/store/apps/details?id=com.st.demo
ST do a lot on NFC and it's worth visiting them here for more info:http://www.st.com/content/st_com/en/search.html#q=NFC-t=products-page=1
You can search ST for MiFare, but there is a good overview of tag types herehttp://www.dummies.com/consumer-electronics/5-nfc-tag-types/
Have fun! Whenever I see NFC at work I am reminded of the Arthur C Clarke quote: "Any sufficiently advanced technology is indistinguishable from magic..."