Choosing a centre stone is one of the most personal decisions you'll make when creating a piece of jewellery.  Each stone has its own character, rarity, and practical considerations. The right choice is one that fits your style, how you intend to wear the piece, and what you want it to represent over time.

This guide explores the natural gemstones we work with, their characteristics, origins, and the practical considerations that come with each. All stones featured are suitable for fine jewellery, each with its own set of practical trade-offs.

During your consultation, we'll guide you through the options based on your lifestyle, aesthetic preferences, and how you intend to wear your jewellery.

Diamonds

Diamonds are the most common choice for fine jewellery centrepieces. Formed deep within the earth under intense heat and pressure over billions of years, they're the hardest naturally occurring material on earth, making them exceptionally well suited to everyday wear.

At A.G, we specialise exclusively in natural mined diamonds. Every diamond is individually selected for its cut, proportions, and overall light performance, as these characteristics have the greatest influence on how a stone looks and performs.

If you're considering a lab grown diamond instead of a natural mined diamond, our sister brand, LOHR Jewellery, specialises exclusively in handcrafted jewellery featuring premium lab grown diamonds. You can explore the collection here.

Features

- Unmatched light performance and brilliance.

- The hardest known natural material, suited to everyday wear.

- A stone whose appeal isn't tied to any particular era or trend.

- Rich historical significance.

Considerations

- Quality varies significantly across cut, colour, clarity, and carat weight.

- Exceptional stones command pricing in line with their rarity.

Yellow Diamonds

Yellow diamonds are natural fancy coloured diamonds. Their colour comes from nitrogen present within their crystal structure. The range runs from soft champagne tones through to vivid canary yellows, with significant variation between individual stones.

Their rarity and natural colour make them a considered alternative to traditional white diamonds, while carrying the same physical durability.

Features

- Naturally occurring colour with no enhancement required in many cases.

- Works particularly well in yellow gold settings.

Considerations

- Colour intensity varies considerably between stones.

- Strongly saturated hues are rarer and priced accordingly.

Pink Diamonds from the Argyle Mine

Pink diamonds are among the world’s rarest and most sought-after gemstones. Their value has increased since the closure of the Argyle Diamond Mine in Western Australia in late 2020, which supplied the vast majority of the world's pink diamonds for almost four decades.

Although the Argyle Mine produced most of the world's pink diamonds, they represented only around 0.1% of its total production. Their rarity began at the source, with each stone taking months to progress from rough crystal to polished, certified diamond.The mine is now permanently closed.

Today, each certified Argyle pink diamond comes from a finite supply. Their documented provenance, exceptional rarity, and enduring global demand place them in a category few gemstones occupy, where provenance is valued alongside beauty and craftsmanship.

A.G has access to a curated selection of certified Argyle pink diamonds available for private viewing. Our team specialises in sourcing certified Argyle pink diamonds through trusted specialist networks and create bespoke pieces that honour their rarity, provenance, and individuality.

Features

- Exceptionally rare with a finite global supply.

- Strong provenance and collectible value, particularly for stones with confirmed Argyle origin.

- Highly sought after in both investment and bespoke jewellery contexts.

Considerations

- Extremely limited availability across all size ranges.

- Pricing reflects their rarity and provenance.

- Typically sourced through private or specialist channels.

Champagne Diamonds

Champagne diamonds are natural diamonds with warm, earthy tones ranging from soft golden hues through to deeper cognac shades. They offer a more a warm, characterful  alternative to white diamonds, with a focus on warmth and individuality.

Features

- Naturally coloured with an organic aesthetic.

- Often more accessible in price than white or fancy coloured diamonds.

- Pairs well with rose and yellow gold settings.

Considerations

- Lower brilliance compared to high colour white diamonds.

Sapphires

Sapphires belong to the corundum family and are most closely associated with deep blue tones, though they occur naturally across a wide range of colours. Their durability and depth of colour make them one of the most enduring choices in fine jewellery. Australian sapphires are particularly valued for their distinctive blue green tones.

At A.G, sapphires are regularly selected as a centre stone for bespoke engagement rings. 

Features

- Exceptional hardness, well suited to daily wear.

- Wide natural colour range.

- A historically significant gemstone with long-established value.

Considerations

- Colour zoning and saturation vary between stones.

- Value is influenced by origin, treatment history, and clarity.

Emeralds

Emeralds are the green variety of beryl, known for their vivid colour and strong visual presence. Their natural inclusions, often called "jardin," are widely accepted as part of their character and aren't treated as defects within the trade.

Each emerald is unique in its internal structure and surface patterning.

Features

- Distinctive, highly recognisable colour.

- Each stone is individual in character.

- Strong historical and cultural significance.

Considerations

- More delicate internal structure than other precious stones.

- Requires considered wear and care to maintain condition.

Tourmaline

Tourmaline occurs in one of the widest natural colour ranges of any gemstone, including green, pink, teal, and two-toned variations. Its variety makes it well suited to bespoke design where individuality is central to the brief.

Features

- Extensive natural colour range.

- Often more accessible than traditional precious gemstones.

- Each stone has its own colour zoning and variation.

Considerations

- Durability varies depending on the variety.

- Colour is not uniform across stones of the same type.

Aquamarine

Aquamarine is a blue to blue-green variety of beryl named for its resemblance to seawater. It's valued for its clarity and consistent colour.

Features

- Clean, consistent colour palette.

- Generally strong clarity.

- A contemporary option that works well in both classic and modern settings.

Considerations

- More subtle colour than many other gemstones.

- Colour can appear lighter under certain lighting conditions.

Ruby

Ruby is the red variety of corundum and one of the most historically significant and highly valued gemstones in fine jewellery. Its red tones range from bright to deep crimson depending on origin and quality.

Features

- Exceptional durability suited to lifelong wear.

- Highly valued with a well-established market.

- Strong, saturated colour with significant visual presence.

Considerations

- Fine quality rubies are rare and priced accordingly.

- Clarity and colour consistency vary considerably between stones.

Citrine

Citrine is a quartz gemstone with warm yellow to amber tones. Its accessibility and versatility make it a practical choice for contemporary jewellery design.

Features

- Warm, consistent colour.

- Accessible and widely available.

- Suitable for everyday wear.

Considerations

- Many stones on the market are heat-treated to achieve their colour.

- Less rare than precious gemstones.