So, I found a way to edit a savegame's inventory using some simple tools. I wouldn't recommend this unless you are just messing around for fun. It is really easy to make your party overpowered and ruin the challenge the game provides. YOU HAVE BEEN WARNED!

You need two tools to do this; A hex editor (I use Hex Workshop) and a program that can compare the Hex offsets of two files(I use Beyond Compare). Both programs have a free trial available

STEP 1) First, go to an Orbal factory and choose a random quartz that you have at least 1 in your inventory of. Next stand close to the counter so you can talk to the shop owner without moving. For this example I will use Defense 1.
[url=http://img.photobucket.com/albums/v288/XaviarCraig/forum%20crap/Step1.jpg~original]http://img.photobucket.com/albums/v288/XaviarCraig/forum%20crap/Step1.jpg~original[/url]

STEP 2) Now you need to save your game preferably in blank slot. For this example I am using Slot 007
[url=http://img.photobucket.com/albums/v288/XaviarCraig/forum%20crap/Step2.jpg~original]http://img.photobucket.com/albums/v288/XaviarCraig/forum%20crap/Step2.jpg~original[/url]

STEP 3) Buy a bunch more of whatever quartz you selected in STEP 1(I am using Defense 1). Since I had 1 I bought 4 more to exaggerate the difference. Remember NOT to move your character otherwise it makes it more difficult.
[url=http://img.photobucket.com/albums/v288/XaviarCraig/forum%20crap/Step3.jpg~original]http://img.photobucket.com/albums/v288/XaviarCraig/forum%20crap/Step3.jpg~original[/url]

STEP 4) Save your game in a new slot. For this example I will use Slot 008.
[url=http://img.photobucket.com/albums/v288/XaviarCraig/forum%20crap/Step4.jpg~original]http://img.photobucket.com/albums/v288/XaviarCraig/forum%20crap/Step4.jpg~original[/url]

STEP 5) Go to the save file location of Legend of Heros Trails in the Sky. Its usually something like;
C:\Documents and Settings\<WINDOWS_LOGIN_NAME>\Application Data\FALCOM\ED6\
For windows Vista/7/8 it should be something like;
C:\Users\<WINDOWS_LOGIN_NAME>\\AppData\Roaming\FALCOM\ED6\
[url=http://img.photobucket.com/albums/v288/XaviarCraig/forum%20crap/Step5.jpg~original]http://img.photobucket.com/albums/v288/XaviarCraig/forum%20crap/Step5.jpg~original[/url]

STEP 6) Open both save files you created in Beyond Compare or something equivalent(Saves 007 and 008 are the ones used in my example). The green box on the side shows RED where there are difference between the two files in the HEX. Scroll down around 2/3 through the file where there should be an isolated red line. This is your inventory area.
[url=http://img.photobucket.com/albums/v288/XaviarCraig/forum%20crap/Step6.jpg~original]http://img.photobucket.com/albums/v288/XaviarCraig/forum%20crap/Step6.jpg~original[/url]

If you notice; Save 007 has "62 02 01 00" at the red boxed area where the other file has "62 02 05 00". I started with 1 Defense 1 Quartz and had 5 Defense 1 quartz when I saved the 2nd time. The "62" is the identifier for Defense 1 quartz. The "02" is signifies that the item is a quartz. The "01 00" or "05 00" depending on which file you are looking at is the quantity you have in your inventory.

Now that you have the value of the quartz and you can determine the location of your inventory you want to find the OFFSET where your current inventory ends. Remember that inventory data is stored as 4 pairs of HEX digits. So you look in the HEX for where there are only pairs of zeros. I have them boxed in toward the bottom in a dark greenish color. Highlight the first repeating pair of zeros and remember the OFFSET location. I boxed it in with purple; "00024DDC"

STEP 7) Open Hex Workshop or something equivalent and open either save file you created(I am using save 007) and go to the OFFSET. For this example will give myself the Quartz with the ID that is 1 higher than "Defense 1". "Defense 1" was "62".

So, we will use the values "63 02 09 00". This should give me 9 quartz with the identifier of "63"
[url=http://img.photobucket.com/albums/v288/XaviarCraig/forum%20crap/Step7.jpg~original]http://img.photobucket.com/albums/v288/XaviarCraig/forum%20crap/Step7.jpg~original[/url]

STEP 8) Load the file you edited and check your Quartz. In my case it was Save 007. It turns out that the quartz with ID "63" is "Defense 2". Now I have 9 of them!
[url=http://img.photobucket.com/albums/v288/XaviarCraig/forum%20crap/Step8.jpg~original]http://img.photobucket.com/albums/v288/XaviarCraig/forum%20crap/Step8.jpg~original[/url]