---
title: "Gemstone Calculator"
slug: "gemstone-calculator"
canonical_url: "https://mahadasha.com/gemstone-calculator"
type: "calculator"
description: "Decide which of the nine navaratna a rising sign licenses and which it refuses, by lordship: the classical triad (lagna lord, 9th lord, 5th lord), a verdict on all nine stones, the incompatibility matrix derived from naisargika maitri, the carat by body weight, and the next computed wearing window."
---

# Gemstone Calculator

Decide which of the nine navaratna a rising sign licenses and which it refuses, by lordship: the classical triad (lagna lord, 9th lord, 5th lord), a verdict on all nine stones, the incompatibility matrix derived from naisargika maitri, the carat by body weight, and the next computed wearing window.


## Inputs

- **ascendant** — rising sign by name; skips the birth data entirely
- **birth_date**, **birth_time**, **latitude**, **longitude**, **timezone** — used only when the ascendant is not given
- **body_weight_kg** — optional; drives the ratti rule, the classical band governs without it

## Programmatic access (for AI agents)

This calculator is backed by a JSON API — agents should call it directly instead of the HTML form:

- **Endpoint:** `POST https://mahadasha.com/api/v1/gemstone/recommend`
- **Auth:** JWT Bearer token — register at `https://mahadasha.com/api/v1/auth/register`
- **OpenAPI schema:** https://mahadasha.com/api/v1/openapi.json
- **API catalog:** https://mahadasha.com/.well-known/api-catalog
- **MCP server card:** https://mahadasha.com/.well-known/mcp/server-card.json

Refer to the OpenAPI schema above for the exact request body and response shape of `https://mahadasha.com/api/v1/gemstone/recommend`.

> Human UI: [Gemstone Calculator](https://mahadasha.com/gemstone-calculator)