@Hawknerd
(LTD) Low Temperature Diamonds are found in ice rings.
Any system you visit , if it has icy rings around a planet you have a potential of finding a LTD hotspot.
Currently everyone is swarming the Borann system because three hotspots are overlapping which increases the chance to find deep core asteroids containing LTD and almost all asteroids in that ring have a percentage of LTD available when laser mining.
Regarding making "gazillions" really fast, be warned that the speed at which you earn credits enables you to buy larger ships which cost more in both upgrading and rebuy. Without having the time at the stick with other ships and in general you might see later in your game where you are spending way more on expensive rebuys which leads to frustration.
I have no problems with you wanting to earn allot of credits really fast, i'm just suggestion while you do that stop to smell the roses. enjoy other aspects of the game not just the current gold rush.