Purple Item Backgrounds on Pickup

[Wilks228]

Whenever you pick up items the image of them pops up on the bottom left, sometimes the images have purple background, but when you look at them in your inventory they just look normal. For me this has happened most often when collecting jelly out of my preserve jars. Does anyone know what this means? Is it to do with the quality of the items?

[Hurodrik]

I believe it has to do with item value.

[GrandpaWorm]

I think it means that the item is worth more than 500g