Base alloys: brass, zamak, and sterling silver — when each one wins
The other day a client walked into the factory in Goiânia, turned one of our necklaces in her hand, and asked me: "Patrícia, is this piece really silver?" I smiled. It was not. It was brass with three-micron 18k plating, like ninety percent of what leaves here. But her question taught me something I still repeat to my resellers today: the client is not asking the name of the metal. She is asking for safety. And safety begins when you know exactly what you have in your hand before you open your mouth.
What a "base alloy" actually is
Every piece of demi-fine has two lives. The outer life, which is the plating — the 18k gold shell the client sees and touches. And the inner life, which is the base alloy: the metal that gives the piece its body, that withstands the clasp closing, the bracelet's friction on the wrist, the fall on the bathroom floor.
I usually say the base alloy is the soul of the piece. The plating is the dress. A beautiful dress over a fragile soul breaks early. Three bases dominate the Brazilian market: brass, zamak, and sterling silver. I will open one at a time.
Brass — the strength and the limit
Brass is an alloy of copper and zinc. It is the workhorse metal of Brazilian demi-fine, and it is what Herreira has worked with since we opened the factory in August 2008.
Why did brass win the market? It is malleable enough that casting can pull thin designs without cracking. It has a warm yellow color that gives the plating a tone close to solid jewelry. And it accepts plating with excellent adhesion, as long as the factory does the pre-treatment correctly (you saw this in the electroplating lesson).
Where does brass stumble? On very sensitive skin. It usually carries residual traces of nickel — below the legal limit, but enough to bother a minority of allergic clients. For them, common brass does not serve. That is why, at Herreira, we keep a hypoallergenic line in parallel, with a barrier that isolates that risk.
Zamak — the popular market's choice
Zamak is an alloy of zinc with aluminum, magnesium, and a bit of copper. It is lighter than brass, cheaper, and it has a wonderful flow into the mold — that is why the popular market loves zamak for pendants full of detail.
But I will be honest with you. Herreira avoids zamak in most pieces. And the reason is technical, not prejudice.
Zamak is more fragile. It takes impact worse than brass, tends to break at the solder point. And, more serious, the plating does not adhere with the same firmness. No matter how careful the factory is with pre-treatment, the gold layer over zamak tends to peel before the same layer over brass. On a daily-wear piece, that becomes a complaint in your hands, not the factory's.
There is quality zamak in the market. But for daily wear, all year long, brass is more loyal. It is what I sleep peacefully selling.
Sterling silver — when the premium is worth it
Sterling silver is another tier. It is 92.5% pure silver mixed with 7.5% copper, which goes in only to give hardness. That is why it is also called sterling.
Here the story changes. Sterling silver is hypoallergenic by nature — no nickel in the composition. For the client who has already had a reaction to other pieces, sterling silver is the safe path. It is what I recommend with closed eyes for anyone with difficult skin.
Sterling silver is also the base of two premium pieces that earn gold in your showcase. The first is the piece with rhodium plating over silver, which becomes what is called white silver — that bright, mirrored white that does not fade like cheaper white gold. The second is vermeil: sterling silver with thick 18k gold plating. Vermeil is the step between demi-fine and solid jewelry, and Herreira has pieces like that in the high line.
The other side of that coin: sterling silver tarnishes. It reacts with sulfur in the air, in sweat, in certain cosmetics. The client needs to know that. Tarnish is not a defect — it is chemistry. And it comes off with a flannel and the right product, in five minutes.
How to sell each one without lying
Here is the heart of the lesson. Three scenes you will live many times.
Scene one. Client asks: "Is this piece silver?" The piece is brass with plating. Your answer: "No, this one is from our 18k plated brass line. It is the most common base in quality demi-fine in Brazil, and the plating here is three microns — thick plating, lasts years. If you are looking for silver, I have it here too, may I show you?"
Scene two. Client says she is allergic to almost everything. Your answer: "Then I will show you two options: our hypoallergenic line, which is brass with a barrier to isolate nickel, and the sterling silver line, which is pure silver with copper — no nickel at all. You can choose by taste, because on the skin side you are protected with both."
Scene three. Client compares your price with the forty-nine reais piece at the mall. Your answer: "That one is usually zamak with thin half-micron plating. Lasts a few months. Mine is brass with three-micron plating. The price is different because what is inside is different."
In none of these scenes do you invent or omit. You name. A client who hears a technical name well-spoken feels she is in safe hands.
Bridge to the next lesson
Now that you can tell brass, zamak, and sterling silver apart, what remains is to understand what happens when we put rhodium over those bases — the plating that turns silver into mirrored white silver and gives a touch of cool jewelry to white gold pieces. See you in lesson 4.