I've been busy data mining in GW2.

This time, I was curious whether magic find affected the chance of getting gems from mining nodes.*

I've seen plenty of questions about magic find and gathering. I've seen speculation on the topic. I've seen assertions given (many assertions). But the wiki isn't much help. And I haven't seen evidence.

So I set about mining.

Every day for the past two weeks, I took each* of my level 80 characters around Tyria gathering orichalcum and any mithril along the way. All characters used orichalcum mining picks and had the guild gathering bonus. One character had 101% MF, the others only had the guild magic find bonus (10%). By the end, I gathered 1027 mithril and 1483 orichalcum.**

Data can be found here.

All told, I didn't see a difference in gems between different levels of magic find.

Node MF N Gem Chance

Mithril 10%: 696 9.5% (1.1)

Mithril 101%: 331 9.4% (1.6)

Orichalcum 10%: 1065 12.0% (1.0)

Orichalcum 101%: 418 12.7% (1.6)

While orichalcum nodes have a higher chance of yielding gems than mithril nodes, I see no difference in the chance of getting gems between 10% MF and 101% MF. (For the stats-nerds, checked with a probit.)

Of course... this is a relatively small sample. So how likely is it that magic find affects the chance of getting gems from mining, but I just didn't notice it? (In stats-language, what is the power of the test, given expectations about the size of the effect being studied.)

To check this, I simulated the results of gathering between 70 to 4200 mining nodes (increments of 70), assuming that magic find works multiplicatively. For each simulation, I checked whether I found that magic find had an effect. (I also included differences between node types, and recorded those.)

From the plot, its clear that after around 1500 mining attempts I'm nearly certain to find an effect from magic find, if one exists. At about 2500 mining attempts (the data I've collected), assuming magic find works, I'd have less than a 1% chance of observing no effect.

**TLDR: magic find doesn't affect the chance of getting gems while mining.**

But, of course, I'll keep gathering data, and check back in if any results listed here change. Because science is the joy of revision.

Related links:

On this blog: MF doesn't affect bags.

From reddit: MF doesn't affect salvaging.

Dev: MF only works on kills.

* Horray for leveling via crafting. I love going from 10 to 70 in like 2 hours.

** Just to be safe, this data excludes any ruined ore / gems from ruined ore. Which is why neither total is divisible by 3.