Have you ever felt like getting a full set of diamond armor is too quick and easy?
Well, you're in the right place. Ores Above Diamonds adds the Amethyst and Black Opal, late-game gems that are far rarer than diamonds, yet also noticeably more powerful.
There is also a 1.12.2 version, 1.14.4 version, 1.15.2 version, 1.16.5 version, 1.17.1 version. and a 1.18.2 version. Look for them in the files tab on the top of the screen.

Amethyst:
Spawns below y:8 (Below y:16 on 1.17-)
Mined by a Diamond+ Pickaxe.
3x rarer than Diamonds.
+50% Efficiency from Diamond.
1.75x Durability from Diamond.
+1 Attack Damage from Diamond
+25 Enchantability from Diamond
+1 Toughness per armor piece from Diamond
80 + 4% Damage Reduction with full set
- Up to 25% tankier than Diamond armor.
1.17+ - Can smash into 3 vanilla amethyst shards
If enabled in the config file, it can spawn in the Nether and the End with significant customizability!
Black Opal:
Spawns below y:0 (Below y:16 on 1.17-)
Mined by an Amethyst+ Pickaxe.
9x rarer than Diamonds.
+100% Efficiency from Diamond.
3.5x Durability from Diamond.
+2 Attack Damage from Diamond
+5 Enchantability from Diamond
+2 Toughness per armor piece from Diamond
80 + 8% Damage Reduction with full set
- Up to +60% tankier than Diamond armor.
If enabled in the config file, it can spawn in the Nether and the End with significant customizability!
1.16+ - Upgrade into Netherite Opal: +1 Attack Damage, +20% efficiency and durability, +1 Toughness, +1 Knockback Resistance, and +5 Enchantability.
(Use a smithing table and add a netherite ingot)
Here is a visualization of the effective health (y-axis) of the armors with respect to the damage (x-axis).
All values are customizable in the config file.
For versions other than 1.12.2, if you are adding this mod to an existing world, the ores only spawn in freshly generated chunks and not preexisting ones. You need to venture far into unexplored lands to have a chance at finding the ores.
Armor can visually cap at 10 full armor bars even though they provide more damage reduction.
For some versions, you can download Overloaded Armor Bar to correct for this.
Config Tutorial
On windows, search %appdata% and click .minecraft -> config and find the oresabovediamonds.toml file.
Most config changes need a full Minecraft restart and/or a full server restart.
For the server owners, the config automatically syncs with the clients! The clients need to join the server, restart their Minecraft, and then rejoin the server. They will be told these instructions automatically upon joining by default. (Disable-able in the config)
1.16.5 and 1.18.1 Expected vs Actual Ore Distribution
1.16.5

Amethyst Expected: 14194 * (7/8) / 3 = 4139
Black Opal Expected: 14194 * (6/8) / 9 = 1182
1.18.1

Amethyst Expected: 57455 / 3 = 19152
Black Opal Expected: 57455 / 9 = 6383
(1.18.1+ vein sizes are all 8, just like diamonds)
Great mods to pair with
Credits
Feel free to leave a comment or send me a PM for any purpose. If it's a bug report, please include the Minecraft version. Suggestions are welcome. Although I'm only going to be maintaining this mod, I would love to hear ideas. I might make a remastered version of this mod down the line.