How to read a strand listing, judge quality, compare sizes and understand pricing.
Bead size is the bead's diameter measured in millimeters. A 4 mm bead is about the width of a grain of rice, and there are 25.4 mm in an inch. Choose 2 to 3 mm for dainty layering, 4 to 6 mm for everyday necklaces, and 8 mm for classic bracelets. These sizes string cleanly and wear comfortably.
We count about 95 to 100 4 mm beads on a 15 inch gemstone strand when beads are touching. Use inches times 25.4, then divide by the bead length along the hole. Deduct about 1.5 inches for clasp and findings when planning a finished piece.
Strand price is set by five things, in order: the stone species, the color grade, the bead size, the cut quality, and the strand length. In US retail, amethyst and labradorite rondelles sit in entry to mid bands. Ethiopian Welo opal small smooths run mid to upper mid. Fine sapphire, especially hand‑faceted briolettes, sits high.
Use quick checks: temperature (stone stays cool longer), a loupe for round gas bubbles or a mold seam at the drill hole, and natural bead-to-bead variation in color and inclusions. Glass warms fast, shows bubbles, and looks identical. Plastic feels light. Price matters too: a way-below-market strand for the stated stone and size is a red flag.
Carats per strand depend on bead size and stone density for the chosen strand length. Use our stone-by-stone strand weights, or estimate with bead counts per inch and IGS formulas. 3 mm sapphire about 20 ct per 8 inches, tourmaline about 17 ct per 8 inches, Ethiopian opal about 20 ct per 8 inches at 4 mm, turquoise about 45 ct per 16 inches at 4 mm.
Do quick, non-destructive checks: rub with a dry cloth for powdering, inspect drill holes for crumble, and lightly click two beads to hear a glassy ping. For bracelets, pick thicker heishi or tall rondelles about 5 mm and up, plus rounded ovals or nuggets with sturdy walls. Skip thin flats and tiny discs on the wrist, and save delicate cuts for earrings or pendants.
Use a digital caliper to spot check diameter on heishi and both diameter and height on rondelles. Measure beads spaced from end to end, note the smallest and largest readings, and compare against the strand's stated size. Accept strands that stay inside the labeled range and read visually even; reject obvious outliers, off-center drilling, or a wobbly silhouette.
Pick strands with bright lemon and orange separated by clean black lines, with bands that continue through each bead. Medium to wide band density reads bold at arm's length. Marquise and pear shapes show banding best. For pendants, choose 25 to 40 mm pieces; for bracelets, use 6 to 8 mm beads or small flats like 9x15 mm pyramids.
Measure the drill height, the center of the hole to the nearest edge. Pick a jump ring whose inner diameter is about twice that distance so it swings freely. For example, a .5 mm drill height needs roughly a 1 mm ID. Choose the thickest wire that passes the hole smoothly.
Count along the drilled axis. On a 16 inch strand, 6 mm along the drill yields about 61 to 66 beads, 8 mm about 46 to 50, 10 mm about 40 and 12 mm about 33. Top drilled pears count by width; center drilled pears, ovals and most rectangles count by length. Half strands hold roughly half of the 16 inch totals.
Check three things: drill height, thickness and symmetry. The hole should sit cleanly across the lobes with solid stone above it. Thickness should suit wear, thinner for bracelets and fuller for pendants. Symmetry should show matched lobes, an even cleft and a centered point so hearts hang straight and feel balanced.