Many named colors start with J across the major catalogs — Wikipedia's color lists, Crayola's crayon catalog, the xkcd Color Survey, gemstone and botanical color vocabularies, and traditional Japanese color names. This page currently lists 22 notable J-color names. No CSS named-color keyword starts with J — the W3C named-color list has no J entry (nor any for Q, U, X, or Z), so every color here comes from other naming traditions.

Several strong candidates. Jade is the classic blue-green named after the prized gemstone — actually two minerals, jadeite and nephrite, with the green varieties most valued. Jet gives English the phrase "jet black," after a hard black variety of lignite (fossilized wood) carved for adornment since antiquity and especially popular for Victorian mourning jewelry. Jonquil is a bright golden yellow named after the fragrant narcissus Narcissus jonquilla. Jasper is a warm red named after the spotted chalcedony gemstone. And Jazzberry Jam and Jungle Green are well-known Crayola crayon colors.

Jet takes its name from the gemstone jet — a hard, black variety of lignite (fossilized wood) that has been carved and polished since the Bronze Age and was especially popular for Victorian mourning jewelry. The word is the origin of the everyday phrase "jet black." Although the cataloged hex (#343434) is a very dark charcoal rather than pure #000000, its near-black character and its namesake both place it most naturally in the Black shade family rather than Gray.

Two of the J-colors on this page are Crayola crayons with documented histories. Per Crayola's own published color history, Jungle Green was introduced in 1990 as one of eight new colors (alongside Cerulean, Dandelion, Fuchsia, Royal Purple, and others). Jazzberry Jam was introduced in 2003 as one of four hues named by Crayola fans for the company's 100th anniversary; it began as an unnamed "Crayon #2" in the 2002 contest pack and received its name through a public vote. The hex values shown are the commonly cataloged digital approximations of the physical crayons.

They are representative, not definitive. Jade is an umbrella term for two minerals — jadeite and nephrite — that occur in green, white, lavender, red, black, and other colors; the green varieties are the most prized, which is why "jade" the color is a blue-green. Jasper is an opaque chalcedony quartz that comes in red, brown, green, and yellow, often patterned (its name traces to the Greek/Latin iaspis, "spotted stone"). Because both gems vary so widely, the hex values here are digital references for the most familiar tone of each, not a single authoritative color.

Not in the way CSS named colors are — and notably, no CSS named-color keyword starts with J, so none of these is fixed by the W3C specification. The values here are widely circulated digital references drawn from public color catalogs, the Crayola crayon range, the xkcd Color Survey, and gemstone/botanical color vocabularies. For pigment-, gemstone-, and plant-named colors (Jade, Jasper, Jonquil, Japanese Indigo), the hex is an approximation of a material whose real appearance varies; for the Crayola colors (Jungle Green, Jazzberry Jam), it approximates a physical crayon whose printed swatch varies slightly across sources.