Rim Frost

I have seen Rim frost (I have also seen it referred to as Rime frost) on leaves, but never on non-nature items. 

Tom took this image a couple of weeks ago on our walkway from our the house in the morning. 

I took this second one at ~6000 feet out West in a Ghost Town on our recent workshop out West. At first I thought that it was slat or a mineral but I picked up another item from the pile and the frost quickly melted by the warmth of my finger tips. Our lcas name is Cuchara which means spoon, so it was fun to find the frost lining this spoon!