Digital Gemology: gemstone and diamond cut library

Digital Gemology MCP servers: cut library, gem identification, gemology lessons, glossary

Four remote Model Context Protocol servers from Digital Gemology:

Server	Endpoint	Registry name	What it does
Cut library	https://digitalgemology.com/mcp	com.digitalgemology/cut-library	Search 40 gem cuts and 5 Platonic solids; ray-traced brilliance, fire and scintillation in seven gemstones; compare cuts; recommend a cut; 3D models and GemCad faceting diagrams
Gem identification	https://digitalgemology.com/mcp/gems	com.digitalgemology/gem-identification	Gemstone properties; match refractive index, birefringence, specific gravity, pleochroism and spectrum lines to seven gemstones; tell two gems apart
Gemology lessons	https://digitalgemology.com/mcp/learn	com.digitalgemology/gemology-lessons	Search, read and quote 53 gemology lessons: the four Cs, diamond anatomy, grading reports, diamond vs moissanite, historic cuts, bow-ties
Gemology glossary	https://digitalgemology.com/mcp/glossary	com.digitalgemology/gemology-glossary	Define 328 gemology terms: every word on a diamond grading report, the four Cs, clarity characteristics, treatments, gem testing, colored gemstones, and how brilliance, fire and scintillation are measured

• Transport: Streamable HTTP, stateless
• Registry: official MCP Registry
• Sign-in: none. Read-only and free to use.
• Protocol versions: 2026-07-28, 2025-11-25, 2025-06-18, 2025-03-26

This repository holds the servers' public description, their registry listings and the open data they serve. The servers run on digitalgemology.com.

Cut library tools (/mcp)

Tool	What it does
search_cuts	Search the cut library by name, style, shape or use ("square step cut", "round brilliant for moissanite", "historic cushion"). Returns each cut's page, facets, size, price and checkout links; give a gemstone to sort by brilliance, fire and scintillation in that stone.
get_cut	Everything about one cut: measured specifications (facets, angles, depth, size, index gear), brilliance, fire and scintillation in all seven gemstones, prices and checkout links.
best_cuts_for_gemstone	The top ten brilliants and top ten jewelry cuts in one gemstone, with the stone's optical constants.
cut_in_gemstone	How one cut performs in one gemstone: eight measured scores against the T73 round brilliant, with pros and cons.
list_gemstones	The seven gemstones (diamond, moissanite, cubic zirconia, ruby, sapphire, emerald, amethyst) with refractive index, critical angle, dispersion, hardness and specific gravity.
get_cut_scores	The Cut Performance Index: overall, brilliance, fire, scintillation, tilt, symmetry, spread, shape-norm and leakage, in all seven gemstones.
compare_cuts	Two cuts side by side in one gemstone: place in the index, every figure, which cut is ahead on each, and links to buy.
recommend_cut	The best cuts for a gemstone, ranked by overall, brilliance, fire, scintillation, spread, tilt or leakage; filter by category or shape.

Gem identification tools (/mcp/gems)

The values that Digital Gemology's free Refractometer, Polariscope, Dichroscope and Spectroscope use, for diamond, moissanite, cubic zirconia, ruby, sapphire, emerald and amethyst. A match is a lead, not an identification: a laboratory report is the proof.

Tool	What it does
gem_properties	One gemstone: refractive index, birefringence, dispersion, specific gravity, hardness, crystal system, and what each instrument shows.
identify_gem	Give any readings (refractive index, birefringence, specific gravity, singly or doubly refractive, pleochroism, a spectrum line, over the refractometer limit). Returns which of the seven stones fit each reading.
compare_gemstones	Which tests tell two gemstones apart (for example diamond and moissanite), and which do not.
absorption_spectrum	The lines and bands a gemstone shows in a spectroscope, with their cause.

Gemology lessons tools (/mcp/learn)

Tool	What it does
search_lessons	Find lessons on a topic or question ("what is fire in a diamond").
get_lesson	The full text of one lesson as Markdown, by title or URL.
explain_term	Short passages from the lessons that explain a term ("critical angle", "pavilion angle"), each with its link.
list_courses	Every course and its lessons.

Gemology glossary tools (/mcp/glossary)

328 terms, each with its own page under digitalgemology.com/learn/glossary. Grading report terms follow GIA, with IGI where it differs.

Tool	What it does
define_term	One term ("crown angle", "feather", "fluorescence", "scintillation"): a short definition, more detail, where it appears on a grading report, how Digital Gemology measures it, related terms, and its page.
search_glossary	Find terms by a word or a question ("what do the girdle words mean", "why does a diamond sparkle").
list_glossary	Every term, or every term in one of 15 topics, with a one-line definition and its page.

Connect

Claude Code

claude mcp add --transport http digital-gemology https://digitalgemology.com/mcp
claude mcp add --transport http digital-gemology-gems https://digitalgemology.com/mcp/gems
claude mcp add --transport http digital-gemology-learn https://digitalgemology.com/mcp/learn
claude mcp add --transport http digital-gemology-glossary https://digitalgemology.com/mcp/glossary

Claude Desktop, Cursor, VS Code and other clients that take a JSON config:

{
  "mcpServers": {
    "digital-gemology": { "type": "http", "url": "https://digitalgemology.com/mcp" },
    "digital-gemology-gems": { "type": "http", "url": "https://digitalgemology.com/mcp/gems" },
    "digital-gemology-learn": { "type": "http", "url": "https://digitalgemology.com/mcp/learn" },
    "digital-gemology-glossary": { "type": "http", "url": "https://digitalgemology.com/mcp/glossary" }
  }
}

Try it with curl

curl -s https://digitalgemology.com/mcp \
  -H "Content-Type: application/json" -H "Accept: application/json, text/event-stream" \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"best_cuts_for_gemstone","arguments":{"gemstone":"moissanite"}}}'

Other ways in

• REST API: https://digitalgemology.com/api/cuts, /api/cuts/{slug}, /api/gemstones, /api/cut-index (OpenAPI)
• JSON files: gem data, all lessons, the glossary, the whole cut library
• A2A agent: https://digitalgemology.com/a2a (agent card)
• For language models: llms.txt, and a Markdown copy of every page
• Docs: digitalgemology.com/about/agents

Data

data/ holds the Digital Gemology Cut Performance Index: ray-traced light-performance scores for 40 gem cuts and 5 Platonic solids in seven gemstones, diamond, moissanite, cubic zirconia, ruby, sapphire, emerald and amethyst (315 rows; 37 cuts are scored, and the rest are listed with the reason). Ruby and sapphire are both corundum, so they share one set of figures; color and absorption are not part of the trace. The method and every column are explained on the index page.

• DOI: 10.5281/zenodo.23844870
• Also on Kaggle and Hugging Face
• Wikidata: Q141955945

License

The data and this documentation are licensed under CC BY 4.0: use and share freely, with credit to Digital Gemology and a link to https://digitalgemology.com. The 3D models and faceting diagrams the tools link to are sold separately under their own license.

Contact

[email protected]