Identify gemstones by refractive index, birefringence, SG, pleochroism and spectrum. Compare 7 gems
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absorption_spectrum Read-only
What a hand spectroscope shows for one gemstone: each absorption line and band with its position in nanometres, its cause (for example Cr3+ in ruby) and what it looks like, from Digital Gemology's Spectroscope.
Gemstone, as its slug.
Install
Pick your client. Values in capitals, like YOUR_TOKEN, are yours to fill in.
claude mcp add --transport http gem-identification https://digitalgemology.com/mcp/gems
Tools (4)
absorption_spectrumWhat a hand spectroscope shows for one gemstone: each absorption line and band with its position in nanometres, its cause (for example Cr3+ in ruby) and what it looks like, from Digital Gemology's Spectroscope.
read-only
What a hand spectroscope shows for one gemstone: each absorption line and band with its position in nanometres, its cause (for example Cr3+ in ruby) and what it looks like, from Digital Gemology's Spectroscope.
| Argument | Type | Description |
|---|---|---|
| gemstone* | string | Gemstone, as its slug. |
Input schema (JSON)
{
"type": "object",
"required": [
"gemstone"
],
"properties": {
"gemstone": {
"enum": [
"diamond",
"moissanite",
"cubic-zirconia",
"ruby",
"sapphire",
"emerald",
"amethyst"
],
"type": "string",
"description": "Gemstone, as its slug."
}
},
"additionalProperties": false
}compare_gemstonesTwo gemstones side by side, and the tests that tell them apart: refractive index, birefringence (doubling of back facets, polariscope), specific gravity, dispersion (fire), hardness, pleochroism and spectrum, each with the free tool that shows it. For questions like 'how do I tell diamond from moissanite?'.
read-only
Two gemstones side by side, and the tests that tell them apart: refractive index, birefringence (doubling of back facets, polariscope), specific gravity, dispersion (fire), hardness, pleochroism and spectrum, each with the free tool that shows it. For questions like 'how do I tell diamond from moissanite?'.
| Argument | Type | Description |
|---|---|---|
| gemstone_a* | string | The first gemstone, as its slug. |
| gemstone_b* | string | The second gemstone, as its slug. |
Input schema (JSON)
{
"type": "object",
"required": [
"gemstone_a",
"gemstone_b"
],
"properties": {
"gemstone_a": {
"enum": [
"diamond",
"moissanite",
"cubic-zirconia",
"ruby",
"sapphire",
"emerald",
"amethyst"
],
"type": "string",
"description": "The first gemstone, as its slug."
},
"gemstone_b": {
"enum": [
"diamond",
"moissanite",
"cubic-zirconia",
"ruby",
"sapphire",
"emerald",
"amethyst"
],
"type": "string",
"description": "The second gemstone, as its slug."
}
},
"additionalProperties": false
}gem_propertiesEverything Digital Gemology measures about one gemstone: refractive index (both rays for doubly refractive stones), birefringence, dispersion, specific gravity, hardness, crystal system, critical angle, what a refractometer, polariscope and dichroscope show, its pleochroic colors and the lines and bands a hand spectroscope shows, with links to the free tools.
read-only
Everything Digital Gemology measures about one gemstone: refractive index (both rays for doubly refractive stones), birefringence, dispersion, specific gravity, hardness, crystal system, critical angle, what a refractometer, polariscope and dichroscope show, its pleochroic colors and the lines and bands a hand spectroscope shows, with links to the free tools.
| Argument | Type | Description |
|---|---|---|
| gemstone* | string | Gemstone, as its slug. |
Input schema (JSON)
{
"type": "object",
"required": [
"gemstone"
],
"properties": {
"gemstone": {
"enum": [
"diamond",
"moissanite",
"cubic-zirconia",
"ruby",
"sapphire",
"emerald",
"amethyst"
],
"type": "string",
"description": "Gemstone, as its slug."
}
},
"additionalProperties": false
}identify_gemMatch a stone's test readings against the seven gemstones Digital Gemology covers and rank them, saying which reading fits and which does not. Give any of: refractive index, birefringence, specific gravity, optic character, pleochroism, a spectrum line, or that the refractometer read over the limit. A match is a lead among seven stones only, not an identification.
read-only
Match a stone's test readings against the seven gemstones Digital Gemology covers and rank them, saying which reading fits and which does not. Give any of: refractive index, birefringence, specific gravity, optic character, pleochroism, a spectrum line, or that the refractometer read over the limit. A match is a lead among seven stones only, not an identification.
| Argument | Type | Description |
|---|---|---|
| pleochroism | string | What the dichroscope shows: none, weak, distinct or strong. |
| birefringence | number | The difference between the two readings, for example 0.008; 0 for a singly refractive stone. |
| over_the_limit | boolean | True if the refractometer showed no reading because the stone is above about 1.81. |
| optic_character | string | From the polariscope: singly refractive (stays dark) or doubly refractive (blinks light and dark). |
| refractive_index | number | A refractometer reading, for example 1.765. |
| specific_gravity | number | Specific gravity, for example 4.0. |
| spectrum_line_nm | number | A line or band seen in a hand spectroscope, in nanometres, for example 694. |
Input schema (JSON)
{
"type": "object",
"properties": {
"pleochroism": {
"enum": [
"none",
"weak",
"distinct",
"strong"
],
"type": "string",
"description": "What the dichroscope shows: none, weak, distinct or strong."
},
"birefringence": {
"type": "number",
"description": "The difference between the two readings, for example 0.008; 0 for a singly refractive stone."
},
"over_the_limit": {
"type": "boolean",
"description": "True if the refractometer showed no reading because the stone is above about 1.81."
},
"optic_character": {
"enum": [
"singly",
"doubly"
],
"type": "string",
"description": "From the polariscope: singly refractive (stays dark) or doubly refractive (blinks light and dark)."
},
"refractive_index": {
"type": "number",
"description": "A refractometer reading, for example 1.765."
},
"specific_gravity": {
"type": "number",
"description": "Specific gravity, for example 4.0."
},
"spectrum_line_nm": {
"type": "number",
"description": "A line or band seen in a hand spectroscope, in nanometres, for example 694."
}
},
"additionalProperties": false
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