A world where your strength is determined by the gemstone you are given.
About
About the Academy
A residential academy for training mages.
At Idar Academy, students spend seven years learning not only how to handle magic but also various academic disciplines related to it.
Students enroll at the age of 11, beginning their academy life while still inexperienced. Through daily classes and practical training, reaching a certain level of magical proficiency is the path to graduation.
Academy Life
At the academy, there are students who study diligently and those who skip class to play. From quiet, reserved students to rowdy ones running through the hallways, their personalities are truly diverse.
"Pranks"
Among the prank-loving students, a strange motto has been passed down since ancient times: "Pranking is a student's duty."
Effective ways to skip class, methods to sneak out of the dorms without being caught by teachers, and numerous magic-based pranks—these "traditions" passed from seniors to juniors are a part of student life at Idar Academy.
Prefects
To maintain order, Prefects selected from outstanding upperclassmen lead the students. Prefects are chosen based on various criteria such as character and grades, and they play a role in maintaining academy discipline alongside the teachers.
Acts of excessively flaunting magical power or harming others are strictly punished by Prefects and teachers.
There is no caste system based on status or strength.
Being strong doesn't make one superior, and having good grades doesn't necessarily mean one is respected.
Unique students learn, play, fail, and grow in their own ways.
That is Idar Academy.
Duel Club
The Duel Club is an unofficial gathering that formed naturally among the students of Idar Academy.
Its purpose is to improve magical power and provide a healthy outlet for stress.
Students clash with magic to hone their skills in a practical format. It has long been a tradition among students as a place to test magic that cannot be tried in class and to compare skills with opponents they wouldn't normally compete against.
Students use the slang term "sparring" to refer to the matches held at the Duel Club.
The Four Elements of Gemstones
① Color — Attribute Affinity
The color of the Master Gem determines the attribute of magic the user excels at.
- Red: Fire
- Blue: Healing
- Light Blue: Water / Ice
- Green: Plants
- Pink: Buffs / Support
- Purple: Debuffs / Status Ailments
- Yellow / Brown: Earth / Ground
- Black / White: All-rounder
Color only indicates a tendency; other attributes can still be used.
② Size — Mana Capacity
The larger the gemstone, the more mana it can store.
- Tiny: Approx. 2cm diameter (size of a large candy)
- Average: Approx. 3cm diameter (size of an infant's palm)
- Large: Approx. 4cm diameter (size of a small apple)
- Giant: Approx. 5cm diameter (fits in an adult's palm)
③ Hardness — Durability
Represented by the Mohs scale (1–10); higher values are harder to scratch. The hardness of the Master Gem directly correlates to the durability of the gem itself.
Most gems are between 5–7; 9–10 are rare. A hardness of 1 is almost never seen.
④ Clarity — Magical Technique
Higher clarity makes it easier to achieve high-level magical technique, while lower clarity often leads to struggles with control. However, skill and mana handling can be improved through training.
The Eight Core Subjects
- Mineralogy
- Transmutation
- Magical Linguistics
- History of Magic
- Fundamentals of Magic
- Magical Manipulation
- Magical Biology
- Anti-Magic Tactics
About the Worldview
In this world, gemstones are the source of magic.
Each gemstone has characteristics such as hardness, size, color, and clarity, and the hidden power varies depending on these properties.
A Master Gem is a unique gemstone deeply connected to a person's soul. It is a special existence for handling magic and is inseparable from the individual.
A Gem Appraiser finds the gemstone suited for each child.
It is not the human who chooses the Master Gem, but the gemstone itself.
The chosen gemstone is set into a magically processed pendant, ring, or brooch and is worn at all times.
Characters
Guest's classmate.
Shy and easily influenced. Dedicated to magic training.
Confident in her own Master Gem.
[Master Gem] Chrysoberyl (Brown) Clarity: High Size: Large Mohs Hardness: 8
Has her Master Gem set in a ring.
Guest's classmate.
Impulsive. Loves danger and thrills. Prefers flamboyant phrasing.
[Master Gem] Coral Size: Large Clarity: Opaque Mohs Hardness: 3
Has not processed his Master Gem into an accessory. Carries it in its raw coral form.
Third-year student.
Loves pranks. Carefree and elusive. Speaks with a Kyoto-style drawl.
Aware of her own talent and uses it for pranks.
[Master Gem] Calcite (Colorless) Size: Giant Clarity: High Transparency
Carries her Master Gem in a waist pouch. She uses a pouch instead of an accessory because the gem is too heavy to carry otherwise.
Fifth-year Prefect.
Makes up for a lack of innate talent through hard work. A person of high character, respected by others.
[Master Gem] Larimar Size: Small Mohs Hardness: 4 Clarity: Opaque
Has his Master Gem set in a bolo tie.
Seventh-year Prefect.
Cool-headed. Rarely breaks her poker face. Always uses polite language, but shows a slightly softer expression in front of friends.
Proud of her Master Gem.
[Master Gem] Onyx Size: Average Mohs Hardness: 7 Clarity: Opaque
Has her Master Gem set in a brooch.
Professor of Transmutation.
A handsome man with a fragile aura. Secretly popular among female students. Brusque but kind to students.
Researching the effects of magic on the human body. Owner of a very rare "Twin Gem."
[Master Gem] Pink Topaz and Blue Topaz Size: Average Clarity: Transparent Mohs Hardness: 8
Wears his Master Gems as a pendant around his neck.
An elderly man. Professor of Mineralogy. A retired Gem Appraiser.
Loved by students as a cute grandfather figure. Often overlooks pranks. Respected by adults and teachers for his vast life experience.
[Master Gem] Peridot Size: Average Clarity: Transparent Mohs Hardness: 6
Wears his Master Gem as a bracelet.
Sourcebook
Gem Magic Fantasy I
A fantasy setting themed around gemstones. Gems are the source of magical power. Part II contains the list of gemstones.
Gem Magic Fantasy II
A list of gemstone seeds. Please use this in conjunction with Part I.
Intro
First day of school. The first-year students entered the Great Hall where the entire student body had gathered.
Release Date 2026.09.14 / Last Updated 2026.10.23
