I’m homebrewing a Jewelcrafting profession for my 5e campaign. Here’s what I’ve got so far. I’ll add to it as I go.

Gems

Gems are split into Common, Uncommon, Rare, Very Rare and Incredibly Rare with the following frequency.

More powerful magical jewelry will require rarer gems.

Common 			55%
Uncommon		30%
Rare 			10%
Very Rare 		04%
Incredibly Rare		01%

Rolling for Gems

If gems are found in loot, you can roll percentile dice to decide on what gem is found.

01 - 55		Common
56 - 85		Uncommon
86 - 95		Rare
96 - 99		Very Rare
00		Incredibly Rare

Jewelcrafters in towns and cities also may be able to trade you gems of similar values but will have limited stock.

Common [d8]

1 Azurite	10 gp 
2 Agate 	10 gp 		
3 Hematite 	10 gp 	
4 Lapis Lazuli 	10 gp 	
5 Malachite 	10 gp 	
6 Obsidian 	10 gp 	
7 Tiger Eye 	10 gp 	
8 Turquoise 	10 gp 

Uncommon [d8]

1 Bloodstone 	50 gp 		
2 Citrine 	50 gp 		
3 Jasper 	50 gp 	
4 Moonstone 	50 gp 	
5 Onyx 		50 gp 	
6 Quartz 	50 gp 
7 Sardonyx 	50 gp 	
8 Zircon 	50 gp 

Rare [d10]

1 Amber 	100 gp
2 Amethyst	100 gp
3 Coral 	100 gp
4 Garnet 	100 gp
5 Jade 		100 gp
6 Jet 		100 gp
7 Pearl 	100 gp
8 Spinel 	100 gp
9 Tourmaline 	100 gp
0 Aquamarine 	100 gp

Very Rare [d6]

1 Alexandrite 	500 gp
2 Black Pearl 	500 gp
3 Jacinth 	500 gp
4 Opal 		500 gp
5 Peridot 	500 gp
6 Topaz 	500 gp

Incredibly Rare [d4]

1 Diamond 	1000 gp
2 Emerald 	1000 gp
3 Ruby 		1000 gp
4 Saphire 	1000 gp

Cutting Gems

Natural gems are unworked. A Jewelcrafter can cut the gem into a more pleasing shape which is worth more.

If you are proficient in a Jeweler’s Toolkit, you can spend 1 hour and make a DEX-based ability check to attempt to cut a gem into a more pleasing shape. Add your proficiency to the check.

  • If the check meets or exceeds the gem’s cutting DC, you increase the value of the gem by 50%.
  • On a failed check, the gem remains unworked and cannot be cut again.
  • Jewelcrafters in larger cities offer this service for 50% of the gem cost.
  • If you have help, you gain advantage on the check.
  • This is not physically straining work so can be performed during a short rest.

Cutting DCs

Use the following DCs to determine the difficulty of cutting a gem.

Common [DC 8]

1 Azurite	10 -> 15 gp 
2 Agate 	10 -> 15 gp 		
3 Hematite 	10 -> 15 gp  	
4 Lapis Lazuli 	10 -> 15 gp 	
5 Malachite 	10 -> 15 gp 	
6 Obsidian 	10 -> 15 gp 	
7 Tiger Eye 	10 -> 15 gp 	
8 Turquoise 	10 -> 15 gp 

Uncommon [DC 10]

1 Bloodstone 	50 -> 75 gp 		
2 Citrine 	50 -> 75 gp 		
3 Jasper 	50 -> 75 gp 	
4 Moonstone 	50 -> 75 gp 	
5 Onyx 		50 -> 75 gp 	
6 Quartz 	50 -> 75 gp 
7 Sardonyx 	50 -> 75 gp 	
8 Zircon 	50 -> 75 gp 

Rare [DC 12]

1 Amber 	100 -> 150 gp
2 Amethyst	100 -> 150 gp
3 Coral 	100 -> 150 gp
4 Garnet 	100 -> 150 gp
5 Jade 		100 -> 150 gp
6 Jet 		100 -> 150 gp
7 Pearl 	100 -> 150 gp
8 Spinel 	100 -> 150 gp
9 Tourmaline 	100 -> 150 gp
0 Aquamarine 	100 -> 150 gp

Very Rare [DC 14]

1 Alexandrite 	500 -> 750 gp
2 Black Pearl 	500 -> 750 gp
3 Peridot 	500 -> 750 gp
4 Topaz 	500 -> 750 gp
5 Opal 		500 -> 750 gp
6 Jacinth 	500 -> 750 gp

Incredibly Rare [DC 16]

1 Saphire 	1000 -> 1500 gp
2 Emerald 	1000 -> 1500 gp
3 Diamond 	1000 -> 1500 gp
4 Ruby 		1000 -> 1500 gp

Initial Recipes

  • To start off, choose 3 out of the following 5 recipes for magical items.
  • Every time one is completed, you gain more knowledge and can choose 1 out of another 3.

Headband of Intellect

wondrous, uncommon (requires attunement)

Your Intelligence score is 19 while you wear this headband. It has no effect on you if your Intelligence is already 19 or higher without it.

Crafting Cost

8x8 hours (64 hours)

  • 1x Gold Chain
  • 1x Jasper
  • 1x Sardonyx
  • 1x Amethyst
  • 1x Aquamarine
  • 1x Pouch of Pixie Dust

Necklace of Adaptation

wondrous, uncommon (requires attunement)

While wearing this necklace, you can breathe normally in any environment, and you have advantage on saving throws made against harmful gases and vapors (such as cloudkill and stinking cloud effects, inhaled poisons, and the breath weapons of some dragons).

Crafting Cost

8x8 hours (64 hours)

  • 1x Silver Necklace Setting
  • 1x Bloodstone
  • 1x Zircon
  • 1x Jasper
  • 1x Citrine
  • 1x Vial of Giant Octopus Ink

Periapt of Wound Closure

wondrous, uncommon (requires attunement)

While you wear this pendant, you stabilize whenever you are dying at the start of Your Turn. In addition, whenever you roll a Hit Die to regain Hit Points, double the number of Hit Points it restores.

Crafting Cost

8x8 hours (64 hours)

  • 1x Silver Pendant Setting
  • 3x Bloodstone
  • 1x Vial of Troll Blood

Ring of Jumping

wondrous, uncommon (requires attunement)

While wearing this ring, you can cast the jump spell from it as a bonus action at will, but can target only yourself when you do so.

Crafting Cost

8x8 hours (64 hours)

  • 1x Silver Ring Setting
  • 1x Moonstone
  • 1x Giant Eagle Feather

Ring of Water Walking

wondrous, uncommon

While wearing this ring, you can stand on and move across any liquid surface as if it were solid ground.

Crafting Cost

8x8 hours (64 hours)

  • 1x Silver Ring Setting
  • 1x Quartz
  • 1x Hulking Crab Claw

I used a few sources to put this together.