
One week and a few hokey pokeys later (I tried shaking the pans, dropping them on the floor, tossing them into the air... everything short of throwing them at the wall), the pigments were still holding together. I even popped a palette of them into my bag to carry around campus and the pigments emerged intact.
Last month, I decided to put them to the ultimate test and popped 3 palettes into a box I was sending back home.
If regular post isn't a test for eyeshadows, I don't know what is it.

Thank goodness it's a colour I don't use often.
After careful inspection, I realised that the Silk Naturals matte, satin and dark shimmer eyeshadows press and hold together better than the lighter hue shimmer eyeshadows. The lighter shimmer eyeshadows showed some flaking while the rest were holding up well after their bumpy journey. Perhaps the shimmer particles don't hold together well or the aloe vera + rubbing alcohol isn't the right mixing medium for these eyeshadows.
If you want to give this mixing medium a go, the ratio is 1/3 of aloe vera gel to 2/3 rubbing alcohol for matte eyeshadows. You need a little more aloe vera gel for pressing the other eyeshadows so 3/7 aloe vera to 4/7 rubbing alcohol (i.e. the aloe vera should be a little less than half of rubbing alcohol) should do.
Another tip: Cover your finger or coin in plastic instead of tissue or a paper napkin before gently pressing the loose eyeshadows into place. There is good reason for this as (1) Tissue gets stuck to the wet eyeshadow, and (2), any red pigments will get soaked up by the paper napkin, making your eyeshadow incredibly hard (it's like working with a brick once it has dried). Plus, the colour is never the same again.
On a random note, all of my loose mineral eyeshadows which I carried in my luggage home ended up exploding all over the place. I have no idea how 10+ lids managed to loosen themselves during an 8 hour flight and make such a mess, especially after I screwed all the lids tight before packaging them. Thank goodness I put them in tupperware. This is goes beyond reason, I swear.