The translucent banded stone of Mies van der Rohe's Villa Tugendhat onyx wall, of every backlit hotel-bar feature wall, of the Ron Arad and Tom Dixon decorative pieces. Architectural onyx is a calcite stone (not the agate-onyx of jewelry, which is silica) precipitated from carbonate-rich water in caves — the same process that builds stalactites, but laid down in horizontal beds. The result is a stone with parallel translucent bands of cream, honey, white, and amber that glows when lit from behind. Backlit onyx panels are the architectural canon since the early 20th century; the Tugendhat wall (1930) is the reference installation. Buy from Antolini, Stone Source, or specialty backlit-stone vendors that pre-laminate onyx slabs to acrylic carriers for safe handling at thin section.
Sedimentary chemical rock, calcium carbonate (calcite, locally aragonite) precipitated from cool ground water in caves and karst environments — the lithified version of stalactite / stalagmite formations, laid down in parallel bands. Density 2700 kg/m³. Mohs hardness 3 (the calcite hardness — soft enough to scratch with a steel knife). Compressive strength 60–95 MPa. Translucency is the key architectural property: a 20mm slab transmits 5–15 percent of incident light, enough for backlit panels to read as glowing. Banding is parallel and tight; pattern variation across a single slab is significant, which is why onyx slabs are typically book-matched (sequential slabs flipped to mirror the pattern). Thinner sections (10–15 mm) are common for backlit installations, often laminated to a clear acrylic / glass carrier for handling and shipping safety. Cuts cleanly with wet diamond saw; carves with calcite-tier ease; takes a high polish on the matrix. Reactive to acid like all calcite stones — citrus juice etches a visible mark within minutes.
Principled BSDF defaults derived from the sphere transparent finish. Reasonable seed for Blender, Substance, Keyshot, Rhino — tune per material. Or grab the whole library at once: ForMaterials library →
# finish: transparent albedo #e0c890 metallic 0.00 roughness 0.05 ior 1.50 transmission 1.00 clearcoat 0.00 sheen 0.00 anisotropic 0.00 thickness 1.00 attenuation_distance 0.60
{
"albedo": "#e0c890",
"metallic": 0.0,
"roughness": 0.05,
"ior": 1.5,
"transmission": 1.0,
"clearcoat": 0.0,
"sheen": 0.0,
"anisotropic": 0.0,
"thickness": 1.0,
"attenuation_distance": 0.6
}
# Blender 4.x — Principled BSDF
# Onyx (Translucent Architectural Onyx) · finish: transparent
import bpy
mat = bpy.data.materials.new(name="mat_onyx_translucent")
mat.use_nodes = True
bsdf = mat.node_tree.nodes["Principled BSDF"]
bsdf.inputs["Base Color"].default_value = (0.7454, 0.5776, 0.2789, 1.0)
bsdf.inputs["Metallic"].default_value = 0.000
bsdf.inputs["Roughness"].default_value = 0.050
bsdf.inputs["IOR"].default_value = 1.500
bsdf.inputs["Transmission Weight"].default_value = 1.000
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
# Onyx (Translucent Architectural Onyx) · finish: transparent
# Run from Window → Scripting Console
import lux
mat = lux.createMaterial(name="mat_onyx_translucent", materialType="Generic")
mat.setProperty("diffuse", (224, 200, 144)) # 8-bit sRGB
mat.setProperty("metallic", 0.000)
mat.setProperty("roughness", 0.050)
mat.setProperty("indexOfRefraction", 1.500)
mat.setProperty("transparency", 1.000)
mat.setProperty("coatingWeight", 0.000)
{
"_format": "Substance Designer / Painter \u2014 pbrMetalRough constants",
"_about": "Onyx (Translucent Architectural Onyx) \u00b7 finish: transparent",
"baseColor": {
"r": 0.7454,
"g": 0.5776,
"b": 0.2789
},
"metallic": 0.0,
"roughness": 0.05,
"ior": 1.5,
"opacity": 0.0,
"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_onyx_translucent",
"pbrMetallicRoughness": {
"baseColorFactor": [
0.7454,
0.5776,
0.2789,
1.0
],
"metallicFactor": 0.0,
"roughnessFactor": 0.05
},
"extensions": {
"KHR_materials_transmission": {
"transmissionFactor": 1.0
}
}
}
]
}# USD Preview Surface — UsdShade.MaterialLook prim attributes
# Onyx (Translucent Architectural Onyx) · finish: transparent
def Material "mat_onyx_translucent" {
token outputs:surface.connect = </mat_onyx_translucent/PreviewSurface.outputs:surface>
def Shader "PreviewSurface" {
uniform token info:id = "UsdPreviewSurface"
color3f inputs:diffuseColor = (0.7454, 0.5776, 0.2789)
float inputs:metallic = 0.000
float inputs:roughness = 0.050
float inputs:ior = 1.500
float inputs:opacity = 0.000
float inputs:clearcoat = 0.000
token outputs:surface
}
}
Marble Institute of America onyx care guide.
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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