I think i got dark matter in cd 2,but i’m not sure…………..maybe it was 3…
Once you’ve sold the items to those Nobles, head back to the Auction, and you’ll find that those greedy Nobles have gone and re-sold them back to the auctioneer, and are once again offered for sale, along with a new item that was previously un-available, the Magical Fingertip. Buy this, (you can also bid on the other items again if you want, but they serve no real purpose anymore other than to boost your treasure hunting rank), then fly to Daguerreo and give it to the old man near the inn for an awesome weapon (I won’t spoil it for you, it’ll ruin the surprise.)
P.S. I find the best way to bid at the Auction, is to head down to the very front of the audience, and press the X button to bring up the ‘place bid’ text box, but, I don’t place any bids yet. Instead, I let the stupid nobles bid back and forth on the item, waiting until the auctioneer says something like "I hear 2000 Gil", then says "2000Gil. Any more?". This is a warning that the item is about to be sold. When he says that, I just place 1Gil more onto the previous bid, and I ALWAYS win the item, and often at a minimum price too! Just remember to take along lots of Gil (around 50000, just to be on the safe side), as those Trenorese are big spenders.
Inceidently, I’m not sure if anyone realises this, but a number of the items for sale in the Treno Auction are actually references to the earlier FF games – Unne from FFI and FFIII, Doga from FFIII, the Rat Tail from FFI and IV etc. Yet another tip-of-the-hat to the previous FF games in FFIX.
The Dark Matter isn’t available until disc 3. The availability of it doesn’t depend on anything else, it will just appear there on its own. Same with the Rat Tail, that’s only there on disc 3.
You can buy these items from the auction again after that, but you can’t sell them back to the nobles. However, if you buy two of the particular items (I think it’s the Une’s Mirror and Griffin’s Heart, but it could be something else…). Then go back to the Black Mage Village on disc 4, and into the hut where the chocobo is. You hear some music from an earlier FF game (FF3j, I think…)