As of writing, this addon adds around 28 new ores that all exist in real life. The ores are Ruby, Sapphire, Sulfur, Celestite, Azurite, Autunite, Magnesite, Alexandrite, Malachite, Crocoite, Graphite, Talc, Silver, Bauxite/Aluminum, Dioptase, Red Beryl, Aquamarine, Pitchblende, Opal, Topaz, Turquoise, Adamite, Amethyst [an easier way to get amethyst shards], Sunstone, Spinel, Tanzanite, Demantoid, Pyrope, and Almandine. It also adds new stone types. As of April 2026 [i edited the description on Apr 18] there is slate, marble, and corundum. Corundum is a host rock for most of the ruby and sapphire you will find. The stone and deepslate variants are a little bit rare. You can polish and make bricks with marble and slate but right now corundum's only use is for getting quick rubies.
Some photos:

[new spinel and amethyst ore textures in 2.0.3, replaced textures made using mcreator's stamp feature]

[a look inside a cave]
If you have any suggestions for new ores, make sure to lmk in the comments! Also, the platform i'm making this mod with [Mcreator], is a little finicky and i can't add stuff like tools or armor right now.