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The Zephyr Sanctum Supply Boxes will likely return with the Festival of the Four Winds, which is scheduled to go live May 20th 2014. Odds are most players will have an abundance of Quartz Crystals, and so prices are dropping rapidly on the trading post. The price dropped around 40% after the announcement was made for the new Festival of the Four Winds. The idea is to welcome Chinese players to the game by hosting an oriental themed festival at the same time.
This is a chance for players to farm some coin, get skins, recipes, etc. Yes, you can buy the quartz crystals when the price hits rock bottom pre patch and hope that there is an increase in demand but most likely we'll get plenty of quartz crystals from the event which will only further drop prices. I would advise that you hang on to your crystals because Jewelcrafting 500 is still coming at some point. Will we need these crystals to help us level? I'm basing this on the possibility of using Charged Quartz Crystals to make Exquisite Charged Quartz Jewels.
Even if I'm wrong about Jewelcrafting 500, I still think you should avoid selling your crystals until after the event ends and prices recover. Selling now will likely result in you watching prices drop below your listing price.
Here are some investment ideas surrounding the event.
I would suggest Gossamer Scraps, Globs of Ectoplasm, and Orichalcum Ore as these are used in crafting with Charged Quartz Crystals. They will likely rise in price during the event.
Also look at this page: http://wiki.guildwars2.com/wiki/Zephyr_Sanctum_Supply_Box
There you'll get ideas under the "Acquisition" part of what you should be investing in right now.