Gemstone Bead Grading

This information page describes the basics of the Gemstone Bead Grading System used by Northern Stones. We often use our grading system for other types of gemstone items as well, and while this page is specifically written for beads the general factors can apply to any gemstone item.

Each bead strand is assigned a letter grade ranging from A to D. At times a plus (+) or minus (-) symbol is used to distinguish strands that are higher or lower in quality within its letter grade. The charts below describe the characteristics of each grade, and show pictures of Natural Lapis Lazuli Round Beads in different grades.

Note: The (A Grade) section goes into greater detail because the tolerances governing it are more strict than within the other grades.



below: (A Grade) below: (B Grade)
above: (C Grade) above: (D Grade)


(A Grade)
The (A+ Grade) is only given to superior bead strands in which every bead on the strand is flawless according to the following criteria. (A Grade) strands are very excellent, and may include only very few minor flaws. (A- Grade) strands are excellent overall, but with more allowable flaws.
Colour

(A+ Grade) beads will be of the most desirable colours within their gemstone family, and each bead on the strand will be exactly the same colour and shade. (A and A- Grade) beads' colour, shade, and consistency stray very little from (A+ Grade). Stones with dye colour enhancements will not make an (A Grade) rating, even if all other aspects of the stone are perfect.

Surface and Shape

Surface and shape are flawless on (A+ Grade) beads, and every bead on the strand is the same shape. The surface and shape of (A Grade) and (A- Grade) are excellent and very uniform, with only very small irregularities allowable.

Polish

Polish is mirror-perfect on (A+ Grade) strands, and will have an overall excellent shine with slight imperfections in (A and A- Grades). The polish will not be enhanced with the use of waxes or coatings (with the exception of Turquoise in which a stabilizing agent assists the polish).

Inclusions

There are no undesirable inclusions in (A+ Grade), while (A and A- Grade) may have some small, stable inclusions. (A+ Grade) beads will have no internal fractures of any kind; and (A and A- Grades) may have tiny natural fractures which are completely stable without having to be glued or artificially enhanced (Turquoise is one of the rare exceptions where it is acceptable to add a stabilizing agent to the stone and maintain an (A Grade) status).

Bead Size

Every bead on an (A+ Grade) strand is the same size (with the exception of graduated strands), and bead size is very consistent on (A and A- Grades). As the bead size gets larger (6mm, 10mm, 14mm... etc..) , perfect gemstone material of large enough scale becomes increasingly rare, and heightens the value of the beads.

Drill Hole

The drill hole on (A+ Grade) strands will be perfectly aligned and formed, and there will be no erosion between neighbouring beads. (A and A- Grade) beads will have excellent drill hole alignment and form, and there may be some minimal erosion between neighbouring beads (which appears as a frosting in the polish where the beads touch).



(B Grade)

Colour

(B Grade) bead strands will be of desirable colours, and may include artificial enhancements such as dying. Though the colour on an individual bead may not be uniform, the complete strand will have a uniform appearance.

Surface and Shape

The shape is very good, with only small variances. The surface may have small natural marks such as voids or fissures, or tiny tool marks.

Polish

The polish is very good, but usually not as bright as (A Grade).

Inclusions

(B Grade) beads usually have inclusions present, though not such that compromise the structural integrity of the stone.

Bead Size

The bead size will be fairly consistent per strand, with minimal differences in size allowable.

Drill Hole

The drill holes are fairly well aligned and formed. Some erosion around the drill holes is usually present (caused when the beads rub together on the strand).



( C Grade)
Colour

( C Grade) bead strands may be of any colour, either natural or dyed. Strands may not be a consistent shade.

Surface and Shape

The surface may include any number of flaws, including chips, cracks, tool marks, pitting, etc. The shape will include irregularities and/or mis-cuts.

Polish

The polish can range from somewhat shiny to dull.

Inclusions

The beads will have a variety of inclusions, from foreign minerals to natural cracks, which may weaken some of the beads. Broken beads are common with ( C Grade), but not necessarily present.

Bead Size

The bead size will be inconsistent per strand, with large differences in size allowable.

Drill Hole

The drill holes can be fairly inaccurate, with poor alignment between beads. Erosion between beads is almost always present. Some beads may have mis-drilled holes, or multiple holes.



(D Grade)
Of the above criteria, (D Grade) will have the most undesirable characteristics to connoisseurs of gemstones and jewellery. Some people, however, prefer (D Grade) because of its natural or earthy appearance. Within this grade you can expect a dull finish, many inclusions, very misshapen beads, very inconsistent bead size, nonuniform colour, broken beads, and any variety of natural or unnatural deformations.