Choosing your stone
The diamond bow-tie effect: how to assess an oval, pear or marquise.
A dark area in one photograph is not a complete diagnosis. Review contrast, movement and proportions before deciding.
The short answer
- Bow-tie appearance depends on the actual faceting and viewing conditions.
- A length-to-width ratio cannot guarantee a bow-tie-free stone.
- Ask for a gentle face-up video in more than one lighting condition.
In this guide
What people mean by a bow tie
Buyers use “bow tie” to describe a bow-shaped contrast pattern across the centre of some elongated brilliant-cut diamonds. In an oval, pear or marquise, that centre can appear darker than surrounding areas. The useful question is how broad, persistent and visually distracting the pattern is in the actual stone—not whether one still image contains any dark facets.
GIA’s published observations of oval, pear and marquise diamonds examine face-up patterns, brightness and observer preference. They show why evaluating fancy shapes requires attention to viewing conditions and the actual facet arrangement. A catalogue outline or a few proportion numbers cannot reproduce the complete observation.
Technical references: [1]
Contrast is not automatically a defect
A diamond is viewed in an environment, with a viewer, camera and light sources around it. As those relationships change, the pattern you see changes. Do not demand that every facet remain bright in every frame: compare whether the centre remains an attractive part of the overall pattern through normal movement.
Equally, do not accept “all ovals have it” as a reason to dismiss a persistent centre that you dislike. Your preference matters. A stone can meet a numerical brief and still be the wrong visual choice for you. Ask for evidence that allows you to judge the effect rather than a verbal reassurance alone.
Technical references: [1]
Request a video that answers the right question
Begin with a face-up view of the actual candidate. Ask for a slow, small tilt rather than fast spinning that hides persistent areas. Request diffuse neutral light as well as a second practical lighting condition. Include enough distance to judge the whole outline, not only a dramatically magnified central facet.
Compare candidates recorded under similar conditions. Different exposure, lighting and rotation speeds can make a worse comparison look persuasive. A report-linked file or clearly identified video helps keep each observation attached to the correct stone. If the clip is only a stock example, it cannot answer the selection question.
- Does the centre change naturally with gentle movement?
- Is a large dark band persistent across the practical views?
- Are the ends and centre visually balanced?
- Do you like the stone at a realistic viewing scale?
- Can the seller identify the exact candidate shown?
Ratio and finish do not replace visual review
Length divided by width describes elongation. Table and depth describe other proportions. These are useful screening information, but neither a preferred ratio nor excellent polish and symmetry alone guarantees a particular light pattern. IGI also distinguishes craftsmanship and proportion assessment from light-performance considerations.
For a pear, inspect the shape as well: the shoulders, rounded end, point and bilateral balance contribute to the silhouette. Think about the intended orientation and protection of the point in the setting. Do not focus on one central feature so intensely that you ignore a lopsided outline or a design that does not suit your brief.
Decide with a comparison, not an internet pass mark
Shortlist two or three candidates meeting your dimensions and budget. Write a sentence about each: outline, central contrast, motion and the feature you most like or dislike. This simple exercise forces you to describe the actual difference rather than copy a universal “ideal ratio” from another buyer.
If available evidence remains insufficient, ask for more imagery or an in-person professional review before committing. There is no honest “zero bow tie guaranteed by this ratio” rule in this guide. Choose the stone whose overall appearance you prefer, with the report and identity checks completed separately.
Common questions
Does a dark centre in a photograph mean I should reject the stone?
Not from that frame alone. Review slow movement and comparable lighting. A persistent pattern you dislike is a valid reason to prefer another candidate.
Can an ideal ratio eliminate a bow tie?
A ratio describes the outline, not the complete facet arrangement or light behaviour. It cannot guarantee the outcome.
Does this apply only to natural diamonds?
No. The visual-selection question also applies to laboratory-grown diamonds cut into these shapes. Growth origin and the observed facet pattern are separate matters.
Sources & editorial method
Prepared with AI assistance and checked against the primary references linked below. Our comparisons, worked examples and buying checklists are editorial guidance, not independent laboratory tests or a professional appraisal. Actual stone details and order terms require separate confirmation.
- GIA research: oval, pear and marquise cut observations (2024) (opens in a new tab)
- IGI: cut grading and light performance (opens in a new tab)
- GIA: selecting a pear-shaped diamond (opens in a new tab)
Technical sources checked on 5 October 2026. Laboratory services and report formats may change; the current issuing laboratory’s record takes precedence.