Minerals & Gemstones on Gor

Four of the others actually carried spears. The spears were large, with curved bronze heads. They seemed heavy. I could not have thrown one.
Captive

Copper on Gor

I saw the scabbard was set with six stones. Emeralds. Perhaps not of great value, but worth taking.
Outlaw

I turned about and looked at the great rock, the granite, streaked with feldspar.
Slave Girl

Other information about Feldspar

Feldspar

Uses of Feldspar

Most salt at Klima is white, but certain of the mines deliver red salt, red from ferrous oxide in its composition, which is called the Red Salt of Kasra, after its port of embarkation, at the juncture of the Upper and Lower Fayeen.
Tribesmen

I turned about and looked at the great rock, the granite. streaked with feldspar.
Slave Girl

We are not fond of men of Port Kar," Ho-Hak said.
There was a rusted, heavy iron collar riveted about the neck of Ho-Hak, with a bit of chain dangling from it.
Raiders

As nearly as I could determine from the map and my memory of the location of the Vosk and the direction I had been carried, I was somewhere in the Voltai Range, sometimes called the Red Mountains, south of the river and to the east of Ar. That would mean that I had unknowingly passed over the great highway, but whether ahead of or behind Pa-Kur's horde I had no idea. My calculations as to my locale tended to be confirmed by the dull reddish colour of the cliffs, due to the presence of large deposits of iron oxide.
Tarnsmen

In the sands of the Stadium in Tharna
Suddenly the foot of Kron swept through the white perfumed sand, bright with mica and red lead, and kicked a broad sheet of particles toward my eyes. It came like a silver and crimson storm, taking me by surprise, blinding me.
Outlaw

Non-gorean information about red lead (used as pigment in paints):
Red Lead
Red Lead Mine

Though the pool was marble and the walkways about it, much of the area was planted with grass and ferns and various other flora were in abundance.
Assassin

In the sands of the Stadium in Tharna
Suddenly the foot of Kron swept through the white perfumed sand, bright with mica and red lead, and kicked a broad sheet of particles toward my eyes. It came like a silver and crimson storm, taking me by surprise, blinding me.
Outlaw

Before Suleiman, now, there lay five stones, three sereem diamonds, red, sparkling, white flecked, and two opals, one a common sort, milky in color, and the other an unusual flame opal, reddish and blue. Opals are not particularly valuable on Earth, but they are much rarer on Gor; these were excellent specimens, cut and polished into luminscent ovoids; still, of course, they did not have the value of the diamonds.
Tribesman

I thrust out the silver paga goblet, studded with rubies, and Telima, standing beside my thronelike chair, filled it.
Raiders

"You will note," he said, "that you wear a common slave leash and collar. There is nothing unusual or valuable about them. The collar, for example, is neither set with sapphires nor is it trimmed with gold. The leash, similarly, is of plain but sturdy material. Both devices are quite ordinary, but, of course, quite efficient."
Kajira

The only mention of quartz in the books is seen here in a wrecked ship of the Priest Kings. All other minerals seem to appear in several places and in ways that suggest the element existed and was available to average Goreans

I then approached the ship, half buried in the grass. I looked inside, trough one of the great rents in the steel. Its edges seemed to have melted and hardened. In places there were frozen rivulets of steel, as though heavy trickles of paint had run from a brush and then hardened. The inside of the ship was black and scorched. The piping, in several places, was ruptured. Panels were split apart, revealing a complex, blackened circuitry within. The heavy glass, or quartz or plastic, in the ports was, in many places, broken through.
Captive

Policrates, sitting beside me, behind the broad, low table, musingly fitted together the two pieces of yellowish, brown stone, the two halves of the once-shattered topaz. Again I found it startling, and impressive, how the figure of a river galley emerged from the brownish discolorations in the two pieces of stone, once they were fitted together. There was no mistaking that they were the two halves of what was once an unusual, divided stone.
Rogue