The J-Smart is a desktop diamond screening device developed and marketed by HRD Antwerp from the mid-2010s. It was the predecessor of the J-Mini Plus and was, alongside the De Beers DiamondView and the early Yehuda devices, one of the first commercially available bench instruments aimed at the dealer and small-retailer market for the segregation of natural colourless diamonds from possible laboratory-grown material.

The device uses short-wave ultraviolet excitation and measurement of the fluorescence and phosphorescence response to flag stones requiring further laboratory testing. As with all screeners of this generation, the J-Smart does not pronounce a positive identification of a synthetic; it places stones into a pass group (overwhelmingly likely natural type Ia diamond) or a referral group (which includes type II naturals and most laboratory-grown stones), with full laboratory analysis required to resolve the referrals.

The J-Smart was effectively superseded by the J-Mini Plus and is now seen mainly in older trade installations. The screening tier of the market has since been crowded by competing devices including the GIA iD100, the De Beers SYNTHdetect XL, the Yehuda Sherlock Holmes series and the GCI MAGI, all addressing the same population-segregation problem with different optical methods and different size ranges.