I finally got that goblin to cough up the moldavite earrings
It was a feeling of great relief as it almost makes my head hurt thinking about the odd times of the day I popped in to attack the goblin. So, in order to alleviate some of the torment, I offer some suggestions based on my experience.
What is the Moldavite Earring?
A moldavite earring is a rare/ex item that can be used at level 47. It simply raises magical attack by 5, and from what I understand, this vastly improves the damage you can cause with spells. This item is of great interest to black mages and red mages. Since it is rare/ex, the only way you can get the earring is to defeat the black mage goblin Mysticmaker Profblix in the Labyrinth of onzozo.
Where do I get it?
The Labyrinth of Onzozo, if you didn't know, is a dangerous place. It's full of very powerful beasts, many of which can turn you to stone, silence you, or at the very least, hit you really hard
There are two goblins that spawn in the same area as Profblix (I've seen bouncers, miners, and hunters). Obviously, they will link if you fight Profblix nearby, and this can be a problem if the fight with Profblix will be close enough as it is. It's a little risky to fight them off (because Profblix might appear while you're doing so) but overall, it's probably best that you do. Also, you could try leading Profblix out of the area along a route that won't drag him by the other two goblins. I've had to do this once when Profblix had already spawned when no one else was around.
The area is also filled with Cockatrices. As a 66 white mage, they left me alone, but they are difficult to fight (silence, petrify, INT reduction... plus they hit hard). If you do get aggro from these monsters, you will have to clear them out of the area as well. You won't want them interfering with your Profblix fight.
Cockatrices and Goblins will attack anyone who rests near them, so be careful! If you do have to rest between fights; there is a nearby ledge behind one of the ponds where it is safe to heal up. Alternatively, you can cast Invisible on yourself or use a Prism Powder just before you start resting.
When do I get it?
The most dreadful part of trying to get Profblix is not knowing when he was defeated. Once defeated, he won't appear again for 2 hours plus anything from 5 to 45 minutes afterwards. So if you show up minutes after he was defeated (and everyone cleared out), you may end up waiting almost 3 hours for him to show up again... all the while, not knowing if he might appear in a few seconds
So, if you know the goblin's time of death, you can minimize your waiting. Even if the place fills up with people trying for the goblin, just knowing when the goblin died will vastly help you in getting him the next time 
The best time to go in my experience has been around suppertime. The area is usually deserted or nearly deserted then, for some reason.
Late at night, is actually the worst. I would have thought 1 in the morning would be the perfect time, but in reality, that's when the most people try for the goblin. Early in the morning isn't much better, either.
How do I get it?
Of course, bringing extra people with you improves your chances. It not only makes the fight easier, but each person makes that much more likely you'll get the claim before anyone else. I'd recommend standing in the middle of the area where Profblix spawns and stand back-to-back with your friends.
I'd suggest having someone who can Provoke with you. Nothing is faster at claiming monsters. But it has a limited range, so bringing a ranged weapon is also good, even if it's a few pebbles. However, most of your competition will be from red mages and black mages (since they want the earring the most). Red mages will cast Dia, but Flash and Stun are even faster, so use those spells if you have them.
The fight itself
Profblix isn't really that hard. Unless he's killed extremely quickly, he will use his two hour ability, Manafont... which is actually pretty silly since he has unlimited mp anyway
You can't silence Profblix so don't even try. Aspir and Drain are nearly useless, as well. Paralyze works wonders however. Keep him paralyzed at all times. Slow also sticks and you can use Dispel on him too.
He will cast a variety of level 2 -ga spells and level 3 elemental spells. His most dangerous magic is Ancient Magic. I've known him to use Freeze and Tornado. He may have others. This magic is strong enough to kill level 75 red mages, so it should be taken very seriously.
First of all, if you or whoever is tanking Profblix has Utsusemi, you're fine. It will absorb all the damage, and since ancient magic has super long casting times, you'll have plenty of time to get the shadows up.
However, if Utsusemi is not available...
Use a bar-spell that corresponds to the element of the ancient magic. I.e. use barblizzara against Freeze and baraera against Tornado. The magic may still hurt a but, but it probably won't kill you. Blink can work as well, but it's unreliable and the spell may hit you anyway. Also, paralyze will occasionally stop Profblix from finishing the spell. Phalanx and Stoneskin can reduce the damage too. From what I've observed, Profblix resists Stun so using that probably won't help you.
Profblix doesn't always drop the earring, so you will likely have to fight him several times. So, you will want to plan to spend a long stretch of time popping into Onzozo throughout the day with two hour breaks in between attempts. It's a good time to finish short quests and missions, or get some farming in.
But once you show up there I'm sure you'll get a feel for it 
