Palette of lightsabers

In order to get a silver crystal, you need to reach the moment in the story where military battles begin on Onderon (there the characters are still separated: 3 characters from the group go to the grave of the Lord Sikhov, and the main character with the old woman and someone else go to Onderon Palace), and after you get into the palace, go left (or right, I don’t remember now), and at the end of the corridor there will be a locked door with a console. In the console, you need to dial the correct combination of numbers and the door will open. The room is the bedroom of the Queen of Onderon! There are three chests to hack in it (you need to have a high hacking skill) and there are 2 lightsabers, random items and a silver crystal! Swords and crystal always lie!!! And anything can be attributed to random objects (somehow I came across a viridian crystal).

Silver from the Rodian, it seems, can be bought after completing her quest. On Nar Shaddaa.

Viridian - In the palace of Queen Thalia on Onderon; The Sith warrior at the very beginning of Trayus Academy on Malachor has 5.
Green - Jungle Dxan;
Orange - Sith Academy on Korriban;
Red - from the Chief Sith Master on Dxan; Darth Sion at the end of the game.

All other crystals do not have a specific place in the game where they would 100% come across.
Yellow - I most often come across from a property seeker near the Jedi Enclave on Dantooine and from a Rodian on Nar Shadaa.
Violet - Mainly found in the Crystal Cave on Dantooine, at the Treasurer near the Jedi Enclave, and in the warehouse next door to Voggi the Hutt on Nar Shadaa.
Blue - I came across it from a duros merchant on Nar Shadaa, in a crystal cave and from a property seeker.
Silver - a very rare crystal, which I came across only in two hard-to-reach places:
1) In the tomb of Friidon Nadd on Dxan. There, in order to open a closed box with parts for a lightsaber (this is where I got this crystal), you need to correctly guess the combination on the terminal (there are 2 boxes and 2 terminals in the tomb). I recommend saving in advance - one mistake, and you will no longer be able to use the terminal for the 2nd time.
2) In the palace of Queen Thalia on Onderon. There, in order to open the locked door to the warehouse, you need to correctly answer all the questions in the terminal near the door. I recommend saving in advance - one mistake, and you will no longer be able to use the terminal for the 2nd time. But that's not all: I recommend taking it with you on a mission in Bao-Dur's palace, as you will need a high hacking skill to open one of the locked boxes in that very warehouse - you will not open it in any other way than hacking.
Bronze - There is no point in looking for this crystal, since bronze and orange crystals give the same color to a lightsaber blade.
Blue is the rarest crystal. I never came across it in the game - I got it through the console, so I don't know where to find it.

I will also add that any of these crystals can come across to you in prize lightsabers, which will be given to you for completing certain story quests.

Teridax [Lord of Shadows]
Add the fact that after talking with Atton (After the destruction of Peragus) You can choose any color. Then, when we reach Datooine, go to the Enclave, there will be a room with the stalker Jerron. He will offer to buy junk, for 1300 credits.When you buy it, you will get your color crystal.Tested on Viridian, Silver and Blue

Crystals of all colors EXCEPT VIRIDINE can be found at all merchants that have color crystals in their assortment, using SaveLoad - before talking to the merchant for the first time, save and open the store menu. If there is no desired crystal, we load up to the moment when we have not yet spoken with the merchant and look at his goods again (for the first time, all items and color crystals are randomly generated as well). Named crystal in the Kinrat cave, it can be light, gray or dark.

Rikudo Nagashi
I have to go to the left, I don't remember if I found a silver crystal there, I definitely found several lightsabers there, and by the end of the game I had crystals of all colors, and three of them were silver