Rubus argutus 'Crystal White' is an heirloom albino blackberry cultivar selected directly from the wild 'Rubus argutus' (the sawtooth blackberry) and propagated as a distinct garden variety. Discovered in the 19th century, it represents a natural mutation that disrupts the plant's anthocyanin biosynthetic pathway. In this variety, the dominant alleles responsible for producing the dark pigments of the wild parent are inactive or absent. This lack of pigmentation yields a fruit that matures to a translucent, creamy-white or pale amber color rather than the characteristic deep black of the typical wild species. Despite this radical change in fruit appearance, 'Crystal White' retains the aggressive, erect, and heavily armored (thorny) cane structure of its wild progenitor.

The fruit of 'Crystal White' is medium-sized, soft, and carries a unique flavor profile that is notably sweeter and less astringent than standard black rubus species. Because it lacks cyanidin-3-glucoside—the anthocyanin responsible for both the black color and the typical sharp tartness of blackberries—the subtle sugars and volatile esters are much more prominent, giving it a flavor often described as a blend of honey and sweet cream. Biochemically, while it is depleted of red and purple pigments, it remains rich in colorless polyphenols such as ellagic acid and various ellagitannins, alongside high levels of Vitamin C. In gastronomic ethnobiology, it stands as a classic historical example of how single-gene color mutations change the sensory and chemical profile of a wild crop.