Small pits, fine bumps and subtle abrasions can turn an otherwise beautiful pearl into an unexpected expense for buyers and owners alike. Which marks are merely superficial, which ones dull the lustre, and how can you spot them before you buy or polish?
This guide explains pearl anatomy and surface characteristics, shows how to set up lighting, organise your workspace and assemble a cleaning kit, and outlines practical visual and tactile inspection methods. It describes how to grade damage, assess its effect on lustre, and decide whether to care for, repair or purchase with confidence.
A guide to pearl anatomy and surface characteristics
A pearl is formed around a central nucleus, surrounded by concentric layers of nacre. Nacre is made up of tiny aragonite platelets held together by conchiolin; the surface orient is responsible for the pearl's colour and subtle flash. The thickness of the nacre determines how much of the underlying growth banding or internal structure is visible. On the surface, minute rounded pits interrupt reflected highlights, small bumps catch the light and cast micro-shadows, and linear abrasions or scuffed areas scatter light and reduce lustre. To inspect a pearl, hold it at arm's length and gently rotate it beneath bright, diffused light to judge the overall lustre. Then use raking light and a 10x loupe to reveal shallow pits, raised beads, polishing marks and fine texture differences.
Wear and contact from settings can alter a pearl’s surface. Examine drill holes and the points where mounts meet the pearl for signs of compression, chipping or residue that may indicate mechanical damage. Inspect growth banding close to the drill and along edges to assess nacre thickness and the risk of an exposed nucleus or delamination. Record findings with close-up photography from multiple angles, keeping lighting consistent to allow reliable comparison. Compare images with reference guides or laboratory descriptions to distinguish natural surface character and growth marks from post-formation damage, supporting evidence-based judgements about condition and durability.
Prefer hook-mounted pearls to assess drill and nacre condition.
Prepare your workspace, refine the lighting and assemble your cleaning kit
Arrange soft, adjustable diffuse lighting with a secondary raking light set at a low angle and a neutral colour temperature. This reduces bright reflections and casts delicate shadows that help reveal small bumps, pits and abrasions. Prepare a stable, uncluttered workspace and use a shallow, dark-coloured tray lined with a soft, non-abrasive cloth to prevent pearls from rolling, enhance contrast and avoid introducing new scratches during handling. Put together a simple cleaning kit of distilled water, a single drop of mild pH-neutral cleanser, a soft-bristled brush or cotton bud, and a microfibre cloth. Clean very gently to begin with, since surface residue can appear like pits, then let pearls air-dry on the soft cloth before you inspect them.
Use magnification and handling aids, for example a 10x jeweller's loupe, a low-power microscope or a hands-free magnifying lamp, to reveal fine surface porosity while keeping both hands free for careful manipulation. Wear finger cots or use soft-tipped tweezers to prevent oils and accidental abrasion from fingertips as you inspect each pearl. Organise a straightforward documentation workflow: label each piece, photograph pearls with a macro or close-up lens alongside a scale, and rotate them to capture the most revealing angles. Record the location and approximate size of any imperfections so you can compare condition before and after cleaning or repair.
Choose a detachable freshwater pearl for easier care.
Identify pits, bumps and abrasions by sight and touch
Organise your inspection area with two light sources and contrasting backgrounds. Use soft, diffuse white light to assess overall lustre, and a low-angle light against both white and dark cards to reveal subtle shadows and how reflections fragment. Employ simple magnification, such as a 10x loupe or your smartphone's macro mode, and photograph the pearl from several angles, then zoom in on the images to detect hairline scratches and concentric wear that are often invisible to the naked eye. Roll the pearl gently between clean fingertips to feel for any catches or wobble, and inspect drill holes and contact points for signs of nacre loss, chips or flattening, which can indicate further abrasion.
Use raking light to reveal tiny shadows cast by pits and raised areas. Hold the pearl against both white and dark cards to see whether reflections stay crisp or break into dull patches, a sign of surface etching or thinning of the nacre. Note the number and distribution of any pits and compare matched pearls for uniformity, photographing defects to monitor any changes over time. When rolling a pearl, apply only light pressure; a smooth roll shows an even surface, whereas a catch, wobble or a lip chip at the drill hole can indicate a pit, a bead outgrowth or prior repair. Base any next step on the severity and position of defects rather than a single blemish, since contact-point wear or thinning around drill holes often predicts future issues.
Choose matched drop pearls for consistent lustre.
How to assess damage and its impact on pearl lustre
Examine pearls under raking light, rotating each slowly so that subtle surface variations reveal themselves. Pits appear as minute dark shadows, bumps as raised highlights and abrasions as smeared or diffuse reflections; record the face on which they appear for grading. Verify your observations with magnification, using a 10x loupe or a stereo microscope, and photograph any defects with macro images alongside a millimetre scale to capture diameter, count and depth. These objective images and measurements provide a reliable baseline for future comparison and tracking.
Apply a consistent rubric to classify damage by size relative to the pearl diameter, depth, count and location, distinguishing minor, moderate and severe cases. Define thresholds to flag exposed or compromised nacre and to note proximity to drill holes or the pearl poles. Assess the effect on lustre by comparing the sharpness and intensity of specular highlights. Gently rotate the pearl to check whether damage causes persistent diffuse scattering, dulled colour play or a loss of mirror-like qualities. Record all observations with annotated photographs and precise measurements, and let that evidence guide any intervention rather than relying on guesswork. Avoid aggressive polishing that will remove nacre, and refer pearls with structural compromise to a professional conservator for stabilisation or conservation rather than attempting risky do-it-yourself repairs.
Choose minimalist studs to protect and showcase inspected pearls
Make confident decisions about care, repair and purchases
Begin by examining each pearl under bright, diffuse light with a jeweller's loupe at around ten times magnification. Rotate the pearl slowly so small pits read as dark shadows, raised areas catch tiny highlights and abrasions appear as dull, matte patches that interrupt the nacre's specular reflections. Lightly run a clean fingertip across the surface, then wipe with a soft, lint-free cloth; if lustre returns after cleaning, the mark is likely a surface deposit rather than structural wear. Inspect drill holes and points of contact under magnification for flaking nacre, thin rims or exposed darker core material, all signs of nacre loss and a greater risk of further deterioration. Note and document these observations so you describe what you see rather than relying on impressions.
Place pearls from the same strand or pair side by side against the same backdrop and in the same light to reveal any mismatch in lustre or surface texture. A consistent appearance suggests uniform quality, while repeated pitting or an uneven gloss can indicate a systemic issue. Record and classify any damage by location, size and depth: tiny surface abrasions that polish or clean away are manageable with regular care, whereas deep pits that expose a different colour beneath the nacre, significant chipping around drill holes, or progressive roughness usually require rethreading, professional restoration, or forgoing the purchase. When possible, request documentation of any treatments or recent repairs to inform your decision.
A confident pearl inspection begins with an understanding of nacre structure. Using diffuse and raking light together with magnification and gentle cleaning will reveal whether marks are superficial or structural. Document any defects with macro photography, and grade them by size, depth and placement to provide objective evidence for assessing their effect on lustre and any potential future risk.
Work methodically through the headings, from anatomy and organising your workspace to detection, grading and decision, ensuring each step informs the next and nothing is overlooked. Retain annotated images, precise measurements and succinct notes so you can make decisions with confidence, track changes over time and preserve colour, lustre and overall condition.