Material Transparency at Copper Master
See how Copper Master documents copper and brass raw materials, interprets Mill Test Certificates, explains chemical composition results, and separates metallurgical evidence from marketing claims.
1. Material Should Be Understood, Not Merely Advertised
Copper, brass, and Kansa can appear strikingly similar once hand-polished, yet they are chemically and functionally distinct. At Copper Master, we believe customers, interior designers, and researchers deserve full access to the primary documentation behind the metal descriptions used throughout our collections.
Pure Copper Raw Material Documentation
Copper is an elemental metal. Its composition is verified through optical emission spectrometry. Below are the exact observed values from Supplier Mill Test Certificate #17342 issued by Mittal Engineering Industries (ISO 9001:2015 & BIS licensed) for pure copper circle lots used in our drinkware:
Brass Raw Material Documentation
Brass is an intentional copper-zinc alloy engineered for malleability, structural rigidity, and warm golden luster. It is not "impure copper." Below are the reported metallurgical parameters from Supplier MTC #17084:
2. What is a Mill Test Certificate (MTC)?
A Mill Test Certificate (also called a certified material test report) is issued by the primary metal smelting and rolling facility for a defined lot. It establishes an auditable chain of custody between raw metal ingots, sheet rolls, and cut circles.
What an MTC DOES prove:
- Chemical purity and elemental composition of the specified raw-material supply lot.
- Mechanical tensile strength, hardness, and ductility under standard metallurgical tests.
- Confirmation that toxic heavy metals such as lead remain at or below defined trace safety thresholds.
What an MTC DOES NOT automatically mean:
- It does not mean every individual finished vessel in our inventory was separately tested in a mass spectrometer.
- It does not constitute a generic BIS product certification for the finished consumer utensil.
- It does not prove health, wellness, or therapeutic medical claims.
3. Supplier MTC vs. Independent Finished-Product Testing
To help buyers assess claims critically across the metalware sector, we present this clear evidence distinction:
4. Why Copper Changes Colour
Unlacquered copper naturally reacts with ambient moisture, oxygen, and water minerals to form a protective cuprous oxide patina. This surface oxidation is natural and expected. Read our dedicated metallurgical guide to understand surface chemistry and safe cleaning:
Read: Why Copper Tarnishes and How to Care for It →