What each stone is, how hard it is, how it is cut for beads, and what to check on a strand.
Labradorite is a plagioclase feldspar whose blue to gold flash, called labradorescence, comes from light bouncing between thin internal layers. To judge a strand, tilt it under one point light and count how many beads show face-up color. More even, face-filling flashes across more beads signals a stronger strand for stringing.
Ethiopian Welo opal, found in 2008 in Ethiopia's Wollo province, is abundant and cut in high volume, so bead strands with real play-of-color usually cost far less than Australian material. White body opal looks opaque to milky; crystal body is transparent. Judge fire by flashes of green, orange and blue from several angles across multiple beads.
Umba sapphire is natural corundum from Tanzania's Umba River valley, known for yielding pinks, oranges, greens and purples from one deposit. Multi sapphire beads are real sapphire, the same mineral as blue sapphire. All colors except red are sapphire, with Mohs 9 hardness. That's why a single strand can show a full, natural color mix.
Test strands under neutral daylight and a white card. Rotate each drilled bead around its hole and face to find the view that reads richest blue violet, then string so that face points outward. For rondelles, align the same face on every bead. For pears and marquise, prefer top-drilled styles and set the broad face forward before you crimp or knot.
Multi tourmaline beads are one mineral strung in many colors. Tourmaline occurs in more colors and color combinations than any other mineral group, so a single strand can run pink, green, blue, olive and brown. Watermelon tourmaline is the bicolor form, a pink core with a green rim. Faceted strands usually run 2 to 4mm because clean rough comes small.
Judge color in daylight first, aiming for an even medium green across the strand. Then scan for surface-reaching lines at the holes and along edges, and feel for snags. Favor thicker, smooth shapes to resist damage. Smooth hearts or pears work well, and fuller ovals do too. Pick substantial rondelles over thin, sharp-edged micro-faceted cuts.
Stronger blue flash shows most consistently on beads 4 mm and larger and on flat or broad-faced shapes like coins, cushions, rectangles, pears, and pyramids. Test under a warm indoor lamp and in daylight. Tilt the strand slightly and rotate; note which beads hold flash under both sources.
Peach moonstone is orthoclase feldspar whose soft apricot body color comes from trace iron and whose floating sheen is adularescence. To choose strands, we look for even color from bead to bead and a sheen that moves as we tilt the strand. Flat, lifeless faces mean the glow is weak.
Pick 3 mm faceted rondelles for the brightest chrome green. 4 mm can work if the beads are shallow and well cut; 5 mm risks going near black. Choose shallow profiles like small rondelles or thin pears to keep color rich. In 3 to 5 mm, avoid tall chunky cuts, uneven drilling, and strands that look yellowish like peridot or show bubbles like glass.
Milky aquamarine is the same beryl as gem aquamarine, but fine internal inclusions make it translucent instead of crystal clear. Colors run from pale blue to green-blue. On a strand, look for even color without gray, consistent translucency from bead to bead, clean drilling, and a balanced layout that graduates smoothly.
For bracelets, choose rounded rondelles or ovals at 6 mm and larger, and avoid 3 to 4 mm and any pointed shapes. For necklaces, rondelles, ovals, pears, or teardrops at 4 mm and up wear more safely; avoid under 3 mm. Heishi discs are risky on wrists due to edge wear, so keep them for necklaces. String with a gentle lay.
Use two quick bench tests. Backlight a single bead with a phone flashlight and sort strands into High, Medium or Low glow by how much light blooms through the body. Then place one bead over printed text; if letters stay readable through the center, it's higher translucency. Choose smooth ovals, pears and teardrops to maximize that inner glow.