Each gemstone has powers corresponding to two stats and will either give proficiency or skills tied to the stat. The attunement grants better stat increase: +2 for the corresponding stats. Also be able to pick 2 skills to be proficient in.
Celeritas: Dexterity and Charisma
Lacertus: Strength and Constitution
Prudentia: Intelligence and Wisdom
Ability saving throws: When you are at attunement level 2 to the stone, you become proficient in one of two saving throws of the corresponding stats, if you are already proficient in all of the stat's saving throw, you can gain an extra feat
Dexterity and Charisma
Skills:
Acrobatics
Sleight of hand
Stealth
Deception
Intimidation
Performance
Persuasion
Strength and Constitution
Skills:
Athletics
Due to low amount of skills, you can also become proficient in:
All armor types
Shields
Simple weapons
Martial weapons
Certain Tools
Range weapons
Intelligence and Wisdom
Skills:
Arcana
History
Investigation
Nature
Religion
Animal Handling
Insight
Medicine
Perception
Survival
Green Gem Space
The ability to store items and people for a indefinite amount of time, with people being in a peak state where no negative effects happens to them
Blue Gem Space
The ability to transport a person into an area to train ones physical attributes, with people being never exhausted and controlled negative effects
Red Gem Space
The ability to teach a person their mental attributes and give them new proficiencies in skills or add more proficiency to a skill they already had