The phrase "Mikimoto pearl strand" refers in trade usage to any single- or multi-row cultured pearl necklace sold by K. Mikimoto & Co. of Tokyo. The phrase is most commonly applied to single-strand Akoya necklaces of the kind for which the company is best known, but the modern Mikimoto catalogue extends well beyond Akoya to include South Sea, Tahitian, and freshwater strands, often combined in graduated or contrasting designs. This article surveys the principal categories and the grading conventions Mikimoto applies to them, with reference to the wider gemmological framework provided by the GIA Pearl Description System.

The Akoya strand

The Akoya strand is the company's signature product. It is built from cultured pearls of Pinctada fucata martensii, the Akoya oyster of the Japanese Pacific coast, in sizes ranging from approximately three millimetres in baby and seed strands to ten millimetres at the upper limit of regular Akoya production. Mikimoto offers Akoya strands at a range of grades, with the company's house designations beginning at A and rising through AA, AAA, and into the A1 and special-grade categories that sit at the top of its grading. In gemmological terms the upper grades correspond to GIA descriptions of excellent or very good lustre, surface cleanliness ranging from clean to lightly blemished, and the rosé or silver overtones characteristic of fine Akoya.

South Sea and Tahitian strands

From the 1980s onward Mikimoto extended its catalogue to include South Sea cultured pearls from the silver- and gold-lipped Pinctada maxima oyster, sourced principally from Australian and Indonesian farms, and Tahitian cultured pearls from the black-lipped Pinctada margaritifera oyster of French Polynesia. South Sea strands are typically produced in sizes from nine millimetres to over fifteen millimetres and in white, silver, and golden body colours. Tahitian strands cover the dark grey to black range with overtones from peacock and aubergine to rose and pistachio. Both categories are graded under the same house framework, modified to recognise the larger size and somewhat thicker nacre of the saltwater South Sea pearl.

Freshwater strands

Mikimoto's freshwater strands, generally produced from cultured pearls of Chinese provenance worked by Hyriopsis cumingii and similar mussels, occupy a different position in the catalogue, intended as a more accessible introduction to the Mikimoto name. The grading is again applied with appropriate adjustments for the different optical character of freshwater nacre, which tends to produce a softer lustre than the steely brightness of fine Akoya.

Stringing and finish

Mikimoto strands are silk-knotted between pearls as standard, a finishing detail that protects each pearl from rubbing against its neighbours and that prevents the loss of the entire strand should the thread part. Clasps are produced in eighteen-karat white or yellow gold or in platinum, and the small Mikimoto logo on the clasp is a deliberate authentication mark. Length conventions follow the standard pearl-trade nomenclature: collar, choker, princess, matinée, opera, and rope, with the princess length of approximately forty-five centimetres serving as the company's most common offering for single-strand Akoya.

Trade significance

The Mikimoto strand is a frequent informal benchmark in the wider pearl trade. Outside Japan, particularly in North America, fine cultured pearl strands from independent producers are sometimes described as being of "Mikimoto quality" as shorthand for the combination of high lustre, clean surface, and careful matching that the company is known for. The shorthand obscures real differences between producers and grades but indicates the standing the Mikimoto name holds. For a buyer evaluating a strand the most useful test remains direct comparison under standardised lighting against a known Mikimoto reference of equivalent size and stated grade.