The magnifying lamp is the workhorse inspection fixture of the jewellery bench. It combines a low-power loupe (typically 1.75x to 5x, occasionally 8x) with a circular fluorescent tube or LED ring around the lens, mounted on an articulated counterbalanced arm clamped to the bench. The bench jeweller uses it for everyday tasks: setting prongs, sizing rings, inspecting solder joints, sorting parcels of small stones and reading hallmarks. It is not used for serious gemmological inspection, where a 10x triplet hand loupe or a binocular gemmological microscope at 10x to 64x is the standard.

Optical quality varies widely. Inexpensive magnifiers use a single plano-convex lens that produces noticeable distortion and chromatic fringing near the edges of the field. Better units use achromatic doublets or, in the upper price range, a flat-field aspheric lens, which holds a sharp focus across the full lens diameter. The major suppliers in the jewellery trade are Luxo, Daylight, Otsuka and Waldmann; bench jewellers tend to buy once and keep for decades.

For LED-illuminated models, the colour temperature of the source matters when judging coloured stone. A nominally daylight 5500K to 6500K source is appropriate for matching to laboratory lighting; warmer tones (3000K to 4000K) shift the apparent colour of yellow, orange and red gems and should not be used for grading. The CRI (colour rendering index) of the LED should be 90 or above for any work involving colour judgement.