Can't find this item
What you found was a Mighty Conjurer Mantle which had a rune attached to it. That rune was called Minor Rune of the Grove, and this gave the ‘of the Grove’ suffix to the name of the item.
In your case, on all of your six pieces of armor (helm, shoulders, etc.) you have a single rune of the Grove. This gives you +10 healing. If you find another Minor Rune of the Grove, or if you buy one from the Trading Post (should be cheap), you will be able to attach it to another piece of armor that doesn’t have a Minor Rune of the Grove on it. If you do that, you will now have 2 pieces of armor with minor runes of the Grove on them, which means you can benefit from both advantages given by the rune. You will have +10 healing and also 10% protection duration.
You should read the article on Runes on the Wiki, for more clarification.