Pearls

Quality natural pearls are very rare jewels. The actual value of a natural pearl is determined in the same way as it would be for other "precious" gems. The valuation factors include size, shape, quality of surface, orient and luster.

Single natural pearls are often sold as a collector's item, or set as centerpieces in unique jewelry. Very few matched strands of natural pearls exist, and those that do often sell for hundreds of thousands of dollars. (In 1917, jeweler Pierre Cartier purchased the Fifth Avenue mansion that is now the New York Cartier store for US$100 cash and a double strand of matched natural pearls valued at the time at US$1 million.)

A pearl strand of the best quality will cost you thousands of Rands. When they are knotted and the strand brake you will just have to look for one pearl, the others are still on the strand. If you loose that one you will still have the other pearls.

I do not think it is neccesary to knot pearls that are coloured and inexpensive. It is time consuming and it does not justify the effort.

Knotting is a next level of proficiency in creating strands. Here the stringing medium (traditionally silk thread or another similar, synthetic medium) has knots tied into it as a means of separating the individual beads from each other. The traditional strand of pearls is a well-known example of this technique. Pearls are threaded onto silk, and a knot is tied between each one to not only space them for greater individual prominence but to also keep them from rubbing directly against each other and risking the abrasion of the nacre that gives them their luster. This classic design can be varied by adding or using other varieties of beads or varying the number and placement of knots used.

Some more notes on pearls below.

A pearl is a hard object produced within the soft tissue (specifically the mantle) of a living shelled mollusk. Just like the shell of a mollusk, a pearl is made up of calcium carbonate in minute crystalline form, which has been deposited in concentric layers. The ideal pearl is perfectly round and smooth, but many other shapes of pearls (baroque pearls) occur. The finest quality natural pearls have been highly valued as gemstones and objects of beauty for many centuries, and because of this, the word pearl has become a metaphor for something very rare, fine, admirable, and valuable.

Valuable pearls occur in the wild, but they are very rare. Cultured or farmed pearls from pearl oysters make up the majority of those that are currently sold. Pearls from the sea are valued more highly than freshwater pearls. Imitation or fake pearls are also widely sold in inexpensive jewelry, but the quality of their iridescence is usually very poor - and generally speaking, artificial pearls are easily distinguished from genuine pearls. Pearls have been harvested and cultivated primarily for use in jewelry, but in the past they were also stitched onto lavish clothing. Pearls have also been crushed and used in cosmetics, medicines, or in paint formulations.

Pearls that are considered to be of gemstone quality are almost always nacreous and iridescent, like the interior of the shell that produces them. However, almost all species of shelled mollusks are capable of producing pearls (formerly referred to as "calcareous concretions" by some sources) of lesser shine or less spherical shape. Although these may also be legitimately referred to as "pearls" by gemological labs and also under U.S. Federal Trade Commission rules,[1] and are formed in the same way, most of them have no value, except as curios

Link to a simple but effective method to know pearls.