Naming Clay, Indigo, and Madder as Soap Colorants

Rose clay, French green clay, indigo powder, madder root, these are the names on the bag and the names in your recipe notes. None of them is what goes on a compliant ingredient panel. INCI naming has its own vocabulary for natural colorants, and it doesn't always match the pretty marketing name a supplier uses.

Why the mismatch happens

INCI names are assigned based on the standardized nomenclature system, which favors chemical or botanical precision over the common name a supplier picked for its packaging. A clay marketed as "French green clay" is a specific type of illite or montmorillonite clay depending on where it's mined, and the INCI name reflects the mineral, not the marketing story around its origin. Same story with plant-based colorants: the common name usually points at the whole plant or its folklore, while the INCI name points at the specific extract or mineral compound actually doing the coloring.

This is a case where working backward from what your supplier calls something can lead you astray if you just write the common name into your ingredient list and call it done.

Clays

Clays used for color and mild exfoliation in soap are typically named by their mineral type. Kaolin is one of the more straightforward ones, since "Kaolin" often is close to or is the INCI name itself, but colored clays like French green, rose, or Moroccan red clay usually need to be traced back to their mineral composition (commonly forms of iron oxide-bearing clay or specific illite/kaolinite mixtures) with your supplier confirming the exact INCI term they use for that specific clay product. Different suppliers sourcing clay from different deposits can end up with different correct INCI names for products that look and behave similarly.

Indigo and other plant-derived colorants

Indigo powder used in cold-process soap for blue and blue-green shades typically traces to an INCI name built around the Indigofera plant, since indigo dye in soap-making is most often derived from Indigofera species processed into a usable powder. Madder root, used for pinks and reds, similarly traces to its botanical source. The exact INCI form depends on how the material was processed, whether it's a whole ground root, a powder, or an extract, and that processing step affects the correct INCI term.

The general pattern for plant-derived colorants:

• Whole dried and ground plant material usually gets named with the plant's Latin genus and species plus a descriptor like "leaf powder" or "root powder"
• Extracts pulled from the plant material get a different INCI form, often ending in "extract"
• Some botanical materials genuinely have no assigned CAS number, which is normal and not a red flag on its own

A working reference

Common name	Typical INCI direction	Notes
Kaolin clay	Kaolin	Often matches or nearly matches the common name
French green / rose / red clay	Mineral-specific clay name, supplier-confirmed	Varies by deposit and supplier processing
Indigo powder	Indigofera-based botanical name	Confirm whole-leaf powder vs extract form with supplier
Madder root	Rubia-based botanical name	Root powder vs extract changes the correct term
Activated charcoal	Charcoal powder	Confirm source material (bamboo, coconut, etc.) with supplier
Turmeric powder	Curcuma longa (turmeric) root/rhizome powder	Common allergen-adjacent skin staining agent, note for customers

Getting the confirmation you need

The reliable move is asking your supplier directly for the INCI name they use on their own documentation, since natural colorant suppliers dealing with cosmetic and soap makers regularly are usually able to hand over this information without friction. Don't guess from the product name on the label, and don't assume two suppliers selling what looks like the same clay are using the same INCI term, because sourcing and processing differences can change it.

Where this fits into your filing

Once you've got the correct INCI names locked down for every colorant in your soap, that's the list that needs to go on your ingredient panel and, if you're filing in Canada, onto your Cosmetic Notification Form. Cosmetic Comply's ingredient matching step is built specifically for this kind of translation work, taking whatever name you have from a supplier and mapping it to the correct INCI and CAS entry before anything gets screened or filed.