Oh, if anyone could help with this, I'd be extremely grateful!

I started noticing a couple of days ago that my young spinach plants have clumps of translucent and VERY tiny (immeasurable with any ruler I have) structures. I know spider mites are supposed to be very small, but I haven't seen any of these move. I am wondering if these are eggs of some sort. They are mostly at the center of the plants, where the leaves all connect and where new growth comes from, as well as being on the backs of the newer leaves, mainly on the bottom of the leaves. There aren't so many on the larger ones. When clustered together, they have a whitish appearance, but they are more translucent individually. I tried taking them off by hand (not individually, obviously). They seem to have a firm texture and a round shape when I rolled them around between my fingers- they didn't break under some pressure from my fingers (I really wasn't attempting it too much, didn't want the mess on my hands from whatever they are!).

I can only post one picture on here but I took two and will have them posted on my gardening blog, linked below. The first picture is a reference- I am a woman with average sized hands, and am holding a small spinach leaf with the "objects" on it- this is so you can sort of get an estimate of how large they are. The second is a closer shot, as best as I could enlarge and still be clear. The pictures in the blog are clickable- they will enlarge to actual size if double clicked on. I am posting the enlarged picture of the leaf on here.

I did notice leafminer in my spinach leaves a few days ago. I picked off all the leaves that had any damage to them or egg cases (very minimal). The affected leaves didn't have the same small translucent structures on them and were mostly on the larger leaves, so I think they are not the same insect....?

Image link:

Here is a link that might be useful: Link to other picture