Yes they are the same thing. Vorici's dialogue options pre-betrayal which you can listen to in this video gave pretty good information on the subject.
Gems represent the one true power here in Wraeclast. The Vaal understood this, the Eternals also. Now, it is our turn to study and exploit these most precious of stones. Geomancy I have come to call the field, and of one thing I am certain. It is we geomancers who shall inherit this fallen Empire, who shall raise this realm to its former glory and beyond.
The Vaal were the first to experiment with the Virtue gems, calling them the Tears of Maji, as mentioned on the History of Wraeclast wiki page. Vorici being a geomancer is related since he was the master related to socket crafting, which is of course how you use skill (virtue) gems.
Virtue gems are so called because they imbue the mundane sack of humanity with virtues normally reserved for the divine. Tenfold when the gem is embedded into flesh and bone rather than a tool of trade. Melding of man and gem... That's a bit of a lost science. The proper fitting of tool with gem however, that can still be mastered by those few with the intellect to fathom it.
Malachai was the "inventor" of gemlings, humans augmented with the virtue gems. Piety tried to recreate this but failed, you can first see her "miscreations" that you fight inside the Act 3 Lunaris temple. Embedding gems into the skin while powerful also corrupts those with the gems. This is why the player has gem sockets in their gear as talked about by Vorici.
The Highgate mines, that's where the virtue gems originated. At the head of the Grantori Vitalis, the aqueduct that runs north from Sarn to the mountains. I procured a few shipping manifests from the docks. The gems were chipped out of the heart of the mountains, and delivered to Sarn by the ton. But from whence do the gems derive their power? Though I'm loath to admit it, even I don't know the answer to that one.
The source of all thaumaturgy including the gems is The Beast, also called Nightmare, which lives in the mountains near highgate. This beast was created by Sin to suppress the power of the gods and has no will of its own. This allowed Thaumaturgists like Malachai and the Vaal before him to mine the virtue gems.
Thaumaturgy resides in everything. Yet our innate ability to harness it is fairly limited. Yes, there are witches who can work minor miracles and Karui holy men who chatter with spirits and call down the rain. They are but amusements playing in the shadow of the gem-wielder. How best to elucidate this... If thamauturgy is the blood, the virtue gem is the heart.
This just goes further to explain that the gems may not be the source, but they are the key or tool that allow you to use the power of thaumaturgy.