Heroic Old-School Roleplaying
Core Rules: Referees Only

Version Beta-0.20.0 / 2025-03-16

Contents

Creatures and NPCs

Creature Saving Throws
HD Death Wielded Paralyze Blasts Spells
0 14 15 16 17 18
1-3 12 13 14 15 16
4-6 10 11 12 13 14
7-9 8 9 10 10 12
10-12 6 7 8 8 10
13-15 4 5 6 5 8
16-18 2 3 4 3 6
19-21 2 2 2 2 4
22+ 2 2 2 2 2
Creature Attack Modifiers
Max HD Mod Max HD Mod
0 -1 9 +7
1 +0 11 +8
2 +1 13 +9
3 +2 15 +10
4 +3 17 +11
5 +4 19 +12
6 +5 21 +13
7 +6 22+ +14

Creatures with bonus hit points (ex: HD X+1) attack as one HD higher.

Gems

Jewelry is worth 3d6 x 100 gp.

Random Gem Values
d20 Gem Value
1–4 10gp
5–9 50gp
10–15 100gp
16–19 500gp
20 80%: 1,000gp, 20%: 5,000gp

Types of Gems by Value

10 gp

  • agate (banded, eye, or moss )
  • azurite
  • hematite
  • lapis lazuli
  • malachite
  • obsidian
  • pearl (freshwater / irregular)
  • quartz (blue)
  • rhodochrosite
  • tiger eye
  • turquoise

50 gp

  • bloodstone
  • carnelian
  • chalcedony
  • chrysoprase
  • citrine
  • iolite
  • jasper
  • moonstone
  • onyx
  • quartz (clear, rose, smoky, or star rose)
  • sard
  • sardonyx
  • zircon

100 gp

  • amber
  • amethyst
  • chrysoberyl
  • coral
  • garnet (red or brown-green )
  • jade
  • jet
  • pearl (white, golden, pink, or silver )
  • spinel (red, red-brown, or deep green)
  • tourmaline

500 gp

  • alexandrite
  • aquamarine
  • garnet (violet)
  • pearl (black)
  • peridot
  • spinel (deep blue)
  • topaz (golden yellow)

1,000 gp

  • emerald
  • opal (white, black, or fire )
  • sapphire (blue, star, or yellow)
  • ruby (star)
  • corundum (fiery yellow or rich purple)

5,000 gp

  • diamond (blue, blue-white, brown, canary, or pink)
  • jacinth
  • ruby (clear red)
  • sapphire (black)

Gem Values by Size and Weight

Unless stated otherwise, a gem is 1/4" in diameter, weighs 2 carats, and is valued based on its composition / type.

Size (Diameter) Weight Value # in 1 cu ft
6" (ex: grapefruit) 31,000 carats / 14 lbs Base value x 50,000 8
3″ (ex: large fist) 4,856 carats / 2 lbs Base value x 5000 64
2″ (ex: cue ball) 1,133 carats / 1/2 lb Base value x 1000 216
1″ (ex: eye ball) 145 carats / 0.064 lbs (16 gems / lb) Base value x 100 1728
1/2″ (ex: marble) 18 carats / 0.008 lbs (125 gems / lb) Base value x 10 13,824
1/4″ (standard) 2 carats / 0.001 lbs (1000 / lb) Base value 110,592
1/8″ (tiny) 0.3 carats / 0.000125 lbs (8000 / lb) Base value / 10 884,736

Adapted from https://olddungeonmaster.com/2012/06/10/gems/ .

This work includes material taken from the System Reference Document 5.1 (“SRD 5.1”) by Wizards of the Coast LLC and available at https://www.dndbeyond.com/srd. The SRD 5.1 is licensed under the Creative Commons Attribution 4.0 International License available at https://creativecommons.org/licenses/by/4.0/legalcode.

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