Exceptional Stones
At Griffin & Sloane, exceptional stones are approached with the same restraint and discernment that defines our watchmaking. We work with a small number of trusted sources and specialists to access diamonds and coloured gemstones of rare quality, selected for their natural character, provenance, and long-term significance.
Rather than maintaining a public catalogue, our role is advisory and curatorial. Stones are sourced in response to specific commissions, guided by context, intent, and suitability. Each acquisition is considered individually, with discretion and long-term stewardship as core principles.
What defines an exceptional stone
Rarity alone is not enough. An exceptional stone is defined by a convergence of factors: natural formation, colour character, clarity, proportion, and provenance. These elements cannot be reduced to a checklist. They require judgement.
In diamonds, this may mean restraint rather than size. In coloured stones, it is often saturation, nuance, and life within the stone that distinguishes the remarkable from the merely fine. Every stone is assessed not only for its individual merit, but for how it will perform within a finished piece over generations.
Diamonds and coloured gemstones
Our experience spans both exceptional diamonds and rare coloured gemstones, including sapphires, emeralds, and rubies. We advise across a wide range of criteria, from traditional grading to subtler considerations such as cut intention, optical behaviour, and suitability for bespoke setting.
Where appropriate, we work with stones of historic or unusual character. In other cases, the brief may call for quiet perfection. The role of Griffin & Sloane is not to impose taste, but to ensure alignment between stone, design, and outcome.
Sourcing with discretion
Access to exceptional stones depends on trust, timing, and clarity of intent. For this reason, stones are sourced privately and by appointment only. We do not hold open inventory, and availability is never guaranteed.
This approach protects discretion for clients, maintains flexibility, and ensures that each stone is selected with purpose rather than convenience. It also allows us to work internationally and opportunistically when the right stone becomes available.
A considered approach
Whether sourcing a stone as the centrepiece of a bespoke jewel, or advising on rarity, value, and long-term suitability, our role is consultative and deliberate. Each discussion begins privately, shaped by context rather than catalogue.
Enquiries are welcomed by private appointment.