This week in Magic finance the biggest gainer by%age was Stock Up, with the Aetherdrift uncommon shooting up more than 800% to just over $4. Perhaps the best Divination ever printed, Stock Up currently shows up in competitive decks from Standard all the way back to Vintage, although as an uncommon it's unlikely the price goes too much higher. 

Meanwhile in Standard, The Enigma Jewel jumped more than 200% this week to just under $9 after posting a solid 7-3 record in Standard in last weekend's Pro Tour Aetherdrift. The Sol Ring for activated abilities hasn't really seen much play in Standard, but thanks to Repurposing Bay, this might be changing. The ability to essentially activate Repurposing Bay for free is quite powerful. Toss in other artifacts with activated abilities like Mazemind Tome and Boommobile and you actually have the core of a powerful deck. Long term I really like The Enigma Jewel. It's the kind of card that gets more and more powerful set by set as more cards with activated abilities are printed, plus it has a weird double-faced mechanic making it awkward to reprint and it's efficient enough to see play in older formats. While the uncertainty is high, it's the type of card that could break out in Modern, Legacy, or Vintage eventually and end up quite expensive if it does.

Finally in Modern, Sickening Shoal is now a $50 card. A week ago it was around $15. This seems to be because it showed up in an Orzhov Blink deck that 5-0'd a league in Modern, although really it's because the card is from an under opened set and has never been reprinted. At this point I'd look to sell [[Sickening Shoal] into the hype. Even if it is good in Modern and maintains its current price, sooner or later it will be reprinted. It seems just as likely that Sickening Shoal was just a random tech card that isn't actually a Modern staple, which would send prices tumbling even faster.