Marg...do these things look anything at all like any vitamin pills or medication that you are taking?? It could be that whatever pills you're taking aren't being digested....so this is a good indication that you can stop taking whatever it is you're taking!
If you don't take any medication at all, then we have to assume that these are some sort of gallstone....? Are they powdery white inside? or....? crystally at all? hmmmmm.
Also..I noticed that you said your stool is tan/orange...but rarely dark brown? The 'perfect poo' is supposed to be dark brown. If your bm's are lighter than that and sometimes orange that means that your bile production isn't great...stagnant...possibly stones blocking it etc...you will know when you remove that stagnation because your bm's will be a darker brown. I've seen that happen to a few people on these forums. All of a sudden they're getting dark bm's! Stuff is beginning to work correctly...
Anyway....let us know about those above white things...pills or...?