Consult

Private diamond concierge · Sydney

Exceptional diamonds.
Without the showroom markup.

Privately sourced natural and lab-grown diamonds. Bespoke craftsmanship, transparent pricing and a more personal way to choose the ring that matters most.

Begin Your Private Consultation Explore Engagement Rings
  • Independently graded diamonds
  • Natural & lab-grown
  • Made to order
  • See your diamond before you commit
  • Insured delivery

The Collection

Engagement rings

Seven signature designs, each made to order and fully customisable: metal, diamond shape, carat, setting and band.

Images are design renders. Every ring is made to order to your chosen diamond, metal and size. Pricing on consultation.

For Him

Men's rings

Wedding bands, signet rings and diamond rings with weight and presence. Made to order in solid gold or platinum, with the same private service.

Buying for both of you? Ask about a matching bridal set, with his and hers designed together.

Three ways to begin

From signature to private commission

Whatever your budget, the same care: real diamonds shown on video, clear specifications and a written quote before anything is made.

i.

Signature Solitaire

Our refined signature designs, set primarily with lab-grown diamonds for exceptional size and brilliance at an accessible price.

  • Six curated designs
  • Choice of metal and shape
  • Ideal starting point
ii.

Bespoke Natural Diamond

An individually sourced natural diamond, hand-selected to your brief and set in a setting tailored to you.

  • Diamonds hand-selected to your brief
  • Grading report with every stone
  • Custom setting adjustments
iii.

Private Commission

For a piece that exists nowhere else. Complex and higher-value designs developed from sketch to CAD to finished jewel.

  • Design consultation
  • CAD render approval
  • Fancy shapes and larger stones

Your diamond, your choice

Natural or lab-grown

Both are real diamonds. The difference is origin, rarity and price. We'll show you both honestly, side by side.

Natural

Formed by the earth

Formed deep underground over immense spans of time. Each is finite and rare, chosen by those who value tradition and natural origin.

Origin
Mined
Rarity
Finite natural supply
Best for
Tradition, heirloom intent
Reports
Independent grading report (e.g. GIA)

Lab-grown

Created by science

Physically, chemically and optically diamond, grown in controlled conditions. Typically allows a larger or higher-grade stone for the same budget.

Origin
Laboratory grown
Material
Real diamond (carbon crystal)
Best for
Size and value
Reports
Independent grading report (e.g. IGI)

Not sure which is right for you? Request a diamond comparison and we'll guide you through both within your budget.

Why choose us

Private luxury. Transparent value.

I

Direct sourcing

Established relationships with diamond suppliers and skilled manufacturers, without the cost of a retail showroom.

II

See it first

You'll see real videos of your actual diamond and its grading report before you commit, not stock images.

III

One consultant

A dedicated consultant guides you privately on WhatsApp, from the first question to the final presentation.

IV

Clear pricing

Itemised written quotes covering diamond, setting and metal. No pressure, no hidden extras.

Our process

How your ring comes to life

Every stage is shared with you through genuine photo and video updates.

Consult

A private WhatsApp conversation about your budget, style, timeline and preferences.

Select

We hand-select diamonds to suit your brief, with grading reports and transparent quotes.

Design

Approve your design and written specification, then secure production with a deposit.

Craft

Your ring is made to order, with progress updates from casting to setting.

Inspect

Quality inspection, then final photos and video of your finished ring before the balance is due.

Deliver

Fully insured, tracked delivery, plus aftercare whenever you need it.

Oval diamond engagement ring on a jeweller's bench beside a design sketch, loupe and Castello box, design renderDesign render

Our story

A heritage in fine jewellery.
A modern approach.

We come from a family of jewellers. The trade has been part of our lives for generations: the language of stones, the discipline of the bench and the understanding that a single piece can carry a lifetime of meaning.

We created this house to offer that knowledge more personally and more transparently. Through long-standing sourcing relationships and skilled manufacturers, we hand-select natural and lab-grown diamonds and craft each ring to order.

Exceptional jewellery should be defined by quality, craftsmanship and meaning, not showroom overheads.

Private by design. Transparent by nature.

Buy with confidence

Trust, built into every step

Graded diamonds

Centre diamonds come with an independent grading report you can verify yourself, online, using the report number.

Approve before we make

Nothing is made until you've approved your diamond, design and written specification.

See before you settle

The final balance is due only after you've seen photos and video of your finished ring.

Secure payments

Formal invoices and reputable, secure payment methods. Every payment is documented in writing.

Insured delivery

Tracked, insured delivery with signature on arrival, discreetly packaged.

Aftercare

Guidance on resizing, cleaning and care, plus support with any concern after delivery.

Questions

Frequently asked

Are lab-grown diamonds real diamonds?

Yes. Lab-grown diamonds have the same physical, chemical and optical properties as natural diamonds. The difference is origin: one formed in the earth, the other in a controlled environment. We always disclose clearly which you are buying, and both come with independent grading reports.

Can I see the diamond before I pay?

Yes. Before you place a deposit you'll receive real videos of your actual diamond and its grading report, so you can compare options properly. After production, you'll see photos and video of the finished ring before the final balance is due.

How do payments work?

Once you approve your diamond and design, a deposit secures production. The balance is due after you've seen your finished ring and before it's dispatched. Every payment is made against a formal invoice through a secure payment method.

How long does it take?

Timing depends on the design and diamond. We'll give you a clear estimate in your written quote. If you have a proposal date in mind, tell us at the start and we'll plan around it.

Why are your prices lower than many retailers?

We work through direct sourcing relationships and don't carry the cost of a retail showroom or large stock. That lets us put more of your budget into the diamond and craftsmanship. Every quote is itemised so you can see exactly what you're paying for.

What if the ring doesn't fit?

We'll help you choose the right size from the start, and guide you through resizing if it's needed. Resizing terms are set out in our warranty and returns policy.

Do you have a showroom?

We are a private, online-first jewellery service. Consultations take place privately on WhatsApp, which lets us keep our overheads low and give you our full attention.

Private consultation

Begin with a conversation

Tell us a little about what you have in mind. Your consultant will reply privately on WhatsApp with guidance and, when you're ready, real diamond options within your budget.

No obligation. No pressure. Complete discretion.

WhatsApp: · Email: hello@maisoncastello.com

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