75% gold, but the silver is mostly gone and copper has taken its place — and the alloy turns pink. The same Au content as 18k yellow gold, the same hardness, the same hallmark, but a color that reads as warmer and softer to the eye even though the metal is no softer than yellow 18k under any test. The pink reads as romantic the way platinum reads as serious. Color is meaning.
Au 75 / Cu ~22.5 / Ag ~2.5 typical. The dominance of copper as alloying element pushes the color into the pink-red half of the gold-color gamut; Cu-rich variants near Au 75 / Cu 25 ("red gold") shade further toward red. Age-hardens through Cu₃Au ordering at 250–350 °C; Vickers ~165 HV achievable. Liquidus ~895 °C. Hallmark .750.
Principled BSDF defaults derived from the sphere metallic finish. Reasonable seed for Blender, Substance, Keyshot, Rhino — tune per material. Or grab the whole library at once: ForMaterials library →
# finish: metallic albedo #d4886a metallic 1.00 roughness 0.25 ior 1.45 transmission 0.00 clearcoat 0.00 sheen 0.00 anisotropic 0.00
{
"albedo": "#d4886a",
"metallic": 1.0,
"roughness": 0.25,
"ior": 1.45,
"transmission": 0.0,
"clearcoat": 0.0,
"sheen": 0.0,
"anisotropic": 0.0
}
# Blender 4.x — Principled BSDF
# 18k Rose Gold · finish: metallic
import bpy
mat = bpy.data.materials.new(name="mat_gold_rose_18k")
mat.use_nodes = True
bsdf = mat.node_tree.nodes["Principled BSDF"]
bsdf.inputs["Base Color"].default_value = (0.6584, 0.2462, 0.1441, 1.0)
bsdf.inputs["Metallic"].default_value = 1.000
bsdf.inputs["Roughness"].default_value = 0.250
bsdf.inputs["IOR"].default_value = 1.450
bsdf.inputs["Transmission Weight"].default_value = 0.000
bsdf.inputs["Coat Weight"].default_value = 0.000
bsdf.inputs["Sheen Weight"].default_value = 0.000
bsdf.inputs["Anisotropic"].default_value = 0.000
# KeyShot 11+ — lux Python API, Generic material
# 18k Rose Gold · finish: metallic
# Run from Window → Scripting Console
import lux
mat = lux.createMaterial(name="mat_gold_rose_18k", materialType="Generic")
mat.setProperty("diffuse", (212, 136, 106)) # 8-bit sRGB
mat.setProperty("metallic", 1.000)
mat.setProperty("roughness", 0.250)
mat.setProperty("indexOfRefraction", 1.450)
mat.setProperty("transparency", 0.000)
mat.setProperty("coatingWeight", 0.000)
{
"_format": "Substance Designer / Painter \u2014 pbrMetalRough constants",
"_about": "18k Rose Gold \u00b7 finish: metallic",
"baseColor": {
"r": 0.6584,
"g": 0.2462,
"b": 0.1441
},
"metallic": 1.0,
"roughness": 0.25,
"ior": 1.45,
"opacity": 1.0,
"anisotropyLevel": 0.0,
"_notes": "Channels listed are the standard Substance pbrMetalRough output. Drop into a Uniform Color node per channel, or as the constant input on a layered stack."
}{
"asset": {
"version": "2.0",
"generator": "ForMatter"
},
"materials": [
{
"name": "mat_gold_rose_18k",
"pbrMetallicRoughness": {
"baseColorFactor": [
0.6584,
0.2462,
0.1441,
1.0
],
"metallicFactor": 1.0,
"roughnessFactor": 0.25
},
"extensions": {
"KHR_materials_ior": {
"ior": 1.45
}
}
}
]
}# USD Preview Surface — UsdShade.MaterialLook prim attributes
# 18k Rose Gold · finish: metallic
def Material "mat_gold_rose_18k" {
token outputs:surface.connect = </mat_gold_rose_18k/PreviewSurface.outputs:surface>
def Shader "PreviewSurface" {
uniform token info:id = "UsdPreviewSurface"
color3f inputs:diffuseColor = (0.6584, 0.2462, 0.1441)
float inputs:metallic = 1.000
float inputs:roughness = 0.250
float inputs:ior = 1.450
float inputs:opacity = 1.000
float inputs:clearcoat = 0.000
token outputs:surface
}
}
World Gold Council; Stuller rose-gold alloy specifications.
House vocabulary — terms ForMatter uses with intent.
Materials and processes for people who design and make things.
A local-first library of materials, processes, applications, and finishes — equal weight, citable everywhere, with cost-over-volume curves, trade-off profiles, equipment-tier filters, and second-life paths layered onto the data so a student can move from "what is this" toward "what's actually buildable here, now, by me." Part of the renato.design ecosystem — sibling of Plenum, Specimen, Ingenue, gesture, graf, and the Renato Rhino plug-ins. Form and matter, inseparable.
Half of teaching materials is teaching how the material is made into the thing. The standard subscription library was always light on that half. The wedge here isn't better samples or a prettier interface — it's treating Process as a peer entity, not a footnote.
Conway's Material World on raw materials, Lefteri's Making It on processes, Forty's Concrete and Culture, Sparke's Design in Context, Bürdek's Design: History, Theory and Practice of Product Design, Schröpfer's Material Design on materials in architecture, Winchester's The Perfectionists on tolerance, Minshall's Your Life Is Manufactured on the global supply chain, von Busch's Making Trouble on material activism, Were's How Materials Matter, Hegger / Drexler / Zeumer's Basics Materials, Untracht and McCreight on metalsmithing, USDA Forest Products Lab on woods, GIA on gemstones, Schott / CoorsTek / Toray / Owens Corning datasheets, MakeItFrom for verifiable property numbers, ASM Handbook, ISO standards. Museum holdings draw from the Met, MAD, V&A, Smithsonian American Art Museum, Newark Museum of Art, British Museum, Heard Museum, Smithsonian NMAI, Eiteljorg Museum, Philadelphia Museum of Art, Cranbrook Art Museum, and Grand Rapids Art Museum — collection-record permalinks only, designer overview pages and exhibition listings excluded. Voice blocks now ride on every entry kind — material, process, application, and finish — and include Ruskin on iron, Anni Albers on twining, Greg Lynn on the shred-and-teeth NURBS lineage, Pugin on the metal that won't be hammered, Barthes / Yanagi / Benjamin channeled within their philosophy; Sparke, Bürdek, Forty, Conway, Schröpfer, Minshall, von Busch, Lefteri, Pat Pruitt, Mary Lee Hu, Tom Joyce, Albert Paley, and the rest of the contemporary makers quoted verbatim with citation. All cited.
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