I actually really love this- or at least, I really love the concept of this, just a very simple and straight forward clicker game , it's pretty awesome you put it together in 3 days, and it's a shame you had IRL stuff to deal with and weren't able to dedicate more time to it.
The character is really cute and simple, and even animated on top of that, the minerals, ore deposits and transmutation orb with table look REALLY REALLY nice. The background tiles are passable, I wouldn't say are "great" like the other sprites, but they definitely are solid enough to where they absolutely do their job of clearly depicting the environment while not being visually displeasing.
The main 2 things I think could have probably been done better in your small timeframe was UI and the balancing of resource values.
UI The first thing the player sees would be the icons for the Bag, the Transmute and Harvest icons also fall under my same criticism, the greys used are incredibly similar to where both the text and icon are fairly hard to see as well as the icon itself giving the impression that it is currently disabled. The text and icons also should have margins so that it fits comfortable within the rest of the icon. For the bag screen, having a second column and shrinking the icons and text sizes slightly would allow everything to comfortable fit on the same screen without the need to scroll down, now there wouldn't be enough space for the digits of how many resources are actually required but I'll be going back to that in the second section. For the transmutation screen, it's fine having the scroll if you want to keep the sizes of stuff large, but it would just be nicer if it was scaled down so that 4 of the 8 recipes were visible on the screen at a time rather than the current 3 and a bit. Resource Values I'm sure this was just wasn't a high priority when you were rushing to put everything together in those 3 days, but I think it very much has effected everyone's experience. I wanted to make the Pinky Stone at the end but after mining for a while when listening to a podcast, I noticed I only had a few tier 3 materials. I was going to bust out the auto clicker but did some quick calculations to see how many resources were actually required to make the end product and even auto-clicking was going to be a big time investment. Here's an illustration just to really get across how insane these resource requirements are:
The player would have to click to harvest ore 540, 672 times to have enough resources to craft 1 Pinky Stone. I think it would been absolutely best to be more mindful and lowball crafting values to something like "4 + 4" for the base requirements where it would look something like this:
Requiring only a total of 2,304 harvest clicks, something that is big enough to take a decent amount of time without it being so insanely grindy that most likely no one is willing to play the game for more than a few minutes.
Hopefully next jam you are able to dedicate more time to your project, I absolutely love clicker/idle games and this would have easily been 5 stars in both categories and not just 1 for me were it to probably even have only 2 or 3 more days put into it. It's perfectly on theme, has great sprites, but not particularly engaging at the moment.
PS: I tried leaving an auto clicker on at the maximum speed while I went to go make some food for probably over 10 minutes and I only managed to get enough light-purple crystals to craft up into this many green gems 
Dx