Different Types Of Gemstones

[aczh1]

In the "Can We Talk About Shardplate" thread (http://www.17thshard.com/forum/forum/19-stormlight-archive/) we started discussing different types of gemstones and their functions. There was very little textual evidence being thrown around, so I started researching, and looked for every reference to gemstones I could find in the books.
 
This is what I found.
 
RUBY: Used in spanreeds. Also used in hearths.
Spanreeds:

Dalinar leaned forward as the familiar—yet indecipherable—lines appeared on the page in stark violet. Faint wisps of reddish smoke floated up from the gemstone.
The spanreeds looked like ordinary writing reeds, except that each had a small infused ruby affixed. The one on the far right pulsed slowly.
She didn’t dare return to her rooms, with all of those sketches accusing her, but there was a desk and a spanreed board in the main room. She sat there, then twisted the ruby.

Description of the function of rubies (back of book)

By infusing a ruby and using methodology that has not been revealed to me (though I have my suspicions), you can create a conjoined pair of gemstones. The process requires splitting the original ruby. The two halves will then create parallel reactions across a distance. Spanreeds are one of the most common forms of this type of fabrial.

Navani's Fabrial (what does it do?)

Navani placed something on her table, a device of polished brass about the size of a fist, with a large, infused ruby at its center. The red Stormlight lit the entire table, throwing shadows down the white tablecloth. Navani picked up the device, rotating it to show her dinner companions its leglike protrusions. Turned that way, it looked vaguely crustacean.

Hearth Fabrial

Adolin glanced at his brother. Renarin stood beside the hearth, inspecting the new fabrial that had been installed there just a few days ago. The infused ruby, encased in a metal enclosure, glowed softly and gave off a comfortable heat. It was convenient, though it felt wrong to Adolin that no fire lay crackling there.
Instead, the hearth held a ruby the size of Kaladin’s fist, one that could have paid to feed everyone in his hometown for weeks.

 

EMERALD: Every gemheart that has been described after it's been taken out of a chasmfiend has been an emerald. Used to make food.
Food

Emeralds were the most valuable, for they could be used by Soulcasters to create food.

Gemhearts

He ripped free the beast’s gemheart—the enormous gemstone that grew within all chasmfiends. It was lumpy and
uncut, but it was a pure emerald

Kaladin lifted the remnants of his coat away from the table, revealing a massive green gemstone. Though bulbous and uncut, the gemheart shone with a powerful inner light.
 
Uncut emeralds, Adolin thought, then looked up to meet Sadeas’s eyes. The man smiled. “The gemstones are recent acquisitions,” Sadeas noted. “I am fond of them.”

 

SAPPHIRE: Whenever a gem attached to Shardplate is mentioned, it is Sapphire (this could be because the Kholin's color is blue, therefore they use Sapphires). Could also be linked to surgebinding. Szeth's eyes turn blue when he uses the surgebinding Honorblade.
Armor

The armor bearers inspected his boots—checking to be certain the laces were tight—then brought a long padded vest to throw over his uniform. Next, they set the sabatons—armor for his boots—on the floor before him. They encased his boots entirely and had a rough surface on the bottoms that seemed to cling to rock. The interiors glowed with the light of the sapphires in their indented pockets.
 
Eight of the ten sapphires used to infuse his Plate were cracked following the battle.”

 
Unknown Fabrial

A large blue gemstone rose into the air, hoisted high on a distant pole near the command tent.

 
Szeth's Eyes

The moment he summoned his Blade, his eyes would turn from dark green to pale—almost glowing—sapphire, a unique effect of his particular weapon.

“Did I Lash you?” the assassin asked in accented Alethi. His eyes had darkened, losing their sapphire blue quality.

 

 

AMETHYST

Gem that contains the angerspren.

She sat on the rock and took the spren-filled gemstone from her pocket, setting it on the ground in front of her. The violet stone glowed with Stormlight.

 
(Back of book)

Reversers: Using an amethyst instead of a ruby also creates conjoined halves of a gemstone, but these two work in creating opposite reactions. Raise one, and the other will be pressed downward, for instance.

 

 

DIAMOND: Used when Shallan soulcast the goblet into blood.

(Assuming this is diamond because it let's out white light). Shardblade pommel

“This is for my men,” Amaram said. He took the Shardblade from the cloth, holding it in his hand. The gemstone at its pommel let out a flash of white light.

Shallan Soulcasting (Pointed out by Paragrin)

The only light in the room came from the three diamond marks in the large crystal goblet on her nightstand.

 

 

HELIODOR(Yellow)

Fabrial that senses people when they come close

She hurried back to the tripod with the fabrial’s box. She slid off the wooden top and removed the large heliodor inside. The pale yellow gemstone, at least two inches in diameter, was fixed inside a metal framework. It glowed gently, not as bright as one might expect of such a sizable gem. (Fabrial that pulses when people come close?)
These fabrials use a heliodor stone as their focus. I do not know whether this is the only type of gemstone that will work, or if there is another reason heliodor is used.

 

 

Jasnah: She uses the diamond to turn a man into crystal, and cracks the smokestone when smiting the two running away. However, when she turns the first man into fire, the ruby is not mentioned at all.

Soulcaster

The gemstones set into Jasnah’s Soulcaster were enormous, some of the largest that Shallan had ever seen, worth many spheres each. One was smokestone, a pure glassy black gemstone. The second was a diamond. The third was a ruby.

“Most of them seek to stop the questions.” Jasnah halted. Then she briefly pulled back her glove, using the light beneath to reveal the street around her. The gemstones on her hand—larger than broams—blazed like torches, red, white, and grey.

 
Soulcasting scene

The other three men began to curse, scrambling away, tripping over one another in their panic. One fell. Jasnah turned casually, brushing his shoulder with her fingers as he struggled to his knees. He became crystal, a figure of pure, flawless quartz—his clothing transformed along with him. The diamond in Jasnah’s Soulcaster faded, but there was still plenty of Stormlight left to send rainbow sparkles through the transformed corpse. The other two men fled in opposite directions. Jasnah took a deep breath, closing her eyes, lifting her hand above her head. Shallan held her safehand to her breast, stunned, confused. Terrified. Stormlight shot from Jasnah’s hand like twin bolts of lightning, symmetrical. One struck each of the footpads and they popped, puffing into smoke. Their empty clothing dropped to the ground. With a sharp snap, the smokestone crystal on Jasnah’s Soulcaster cracked, its light vanishing, leaving her with just the diamond and the ruby.

 
 
If you guys find any text evidence I've missed, I'll gladly edit this post and add it in (and credit you of course!)

Edited March 26, 2015 by aczh1

[Paragrin]

I would like to point out that we only see Jasnah Soulcast into the three Essences that match her gemstones - and each time she does, the corresponding gemstone goes dark. She could be doing this deliberately to maintain the illusion of the fabrial, but it bears noting. Do we know the gem Shallan uses to turn the goblet to blood?

[WeiryWriter]

This page might help.

 

Edit:

 

 

I would like to point out that we only see Jasnah Soulcast into the three Essences that match her gemstones - and each time she does, the corresponding gemstone goes dark. She could be doing this deliberately to maintain the illusion of the fabrial, but it bears noting. Do we know the gem Shallan uses to turn the goblet to blood?

 

We do, she uses a garnet.  Soulcasting is unique in that the kind of gem the stormlight comes from has an effect on what it can be used for.

Edited March 26, 2015 by WeiryWriter

[aczh1]

Huh, seems like this was already done! Should've looked harder on the wiki. You can delete this thread, it's obsolete