Is tanzanite heat-treated, and what does that mean for the beads?

Nearly all tanzanite on the market is heat-treated. Rough from the Merelani Hills typically comes out of the ground brownish or yellow-green; controlled heating around 500°C drives the vanadium-bearing zoisite to the blue-violet color the trade recognizes as tanzanite. The treatment is stable, permanent under normal wear, and not considered a defect — untreated material is rare and usually sold as a specialty. Heating doesn't affect hardness or require special care beyond what's already advised for tanzanite.

What jewelry projects suit tanzanite beads best?

Tanzanite at Mohs 6.5–7 with distinct cleavage is best routed to low-impact pieces: earrings, pendants, lariats, and necklaces where beads aren't taking knocks. Avoid stacking bracelets and ring-adjacent designs where bead-on-bead or bead-on-hard-surface contact is constant. The cut sizes Dakota stocks lean small — 3mm and 4mm rounds, microfaceted rounds, and rondelles — which suits delicate strung work, multi-strand layering, and accent placement alongside gold-fill or sterling findings. Faceted cuts pull the most color saturation out of smaller beads; smooth rounds read quieter and pair well with pearl, moonstone, or labradorite for cool-palette work.

How do I care for finished pieces with tanzanite beads?

Clean with mild soap, lukewarm water, and a soft cloth — nothing more aggressive. Skip ultrasonic and steam cleaners; the cleavage planes in zoisite make tanzanite vulnerable to fracture from vibration and thermal shock. Avoid sudden temperature swings (don't move from hot car to cold AC), and keep finished pieces away from household chemicals, chlorine, and acidic cleaners. Store tanzanite strands separately from harder stones like quartz, topaz, or corundum that can abrade the surface. For customers, advise removing tanzanite jewelry before exercise, gardening, or anything involving impact.

What stones get confused with tanzanite in the bead trade?

Three come up most often. Iolite shares the violet-blue range but shows stronger pleochroism and is typically darker and less saturated; it's also significantly cheaper per strand. Blue sapphire beads run harder (Mohs 9) and hold a more pure blue without the violet flash. Generic zoisite — the parent mineral — is sold in green and pink varieties and shouldn't be marketed as tanzanite, which refers specifically to the blue-violet gem variety from the Merelani Hills. Dyed quartz and synthetic spinel sometimes appear at suspiciously low price points; genuine tanzanite carries a recognizable cost floor even in small bead sizes.

Why does color vary between tanzanite strands at the same size?

Tanzanite is pleochroic — it shows different colors (blue, violet, sometimes burgundy) along different crystal axes. How rough is oriented during cutting determines whether a finished bead reads more blue or more violet, and saturation depends on the depth of the bead and the quality of the source rough. Smaller beads (2–4mm) generally show lighter tone because less material means less color path; larger or faceted beads concentrate saturation. Strand-to-strand variation is normal and not a defect. If color matching across multiple strands matters for a production run, buy strands together from the same lot when possible.

Tanzanite 4mm Coin Faceted AA Grade - 15-16 Inch

$67.00 - $67.00

$67.00

$67.00 - $67.00

$67.00

Tanzanite is both extremely rare and extremely attractive, and we offer it when we can.

SKU TAN4DC-F-AA

Product Specifications

Stone type

Zoisite

Cut

Faceted coin

Bead size

4mm

Strand length

15-16 Inch

Approx. beads / strand

100

Drill style

Center-drilled (face to face)

Hole size

0.8-1.1mm

Grade

AA Grade

Mohs hardness

6.5–7

Mineral family

Zoisite

Treatment

Heated

Typical origin

Tanzania (Merelani Hills)

Care

Moderate-hard (Mohs 6.5–7) but cleavage planes make it impact-sensitive. Avoid ultrasonic, steam, and sudden temperature changes; mild soap and soft cloth.

Frequently asked questions

Is tanzanite heat-treated, and what does that mean for the beads?

Nearly all tanzanite on the market is heat-treated. Rough from the Merelani Hills typically comes out of the ground brownish or yellow-green; controlled heating around 500°C drives the vanadium-bearing zoisite to the blue-violet color the trade recognizes as tanzanite. The treatment is stable, permanent under normal wear, and not considered a defect — untreated material is rare and usually sold as a specialty. Heating doesn't affect hardness or require special care beyond what's already advised for tanzanite.
What jewelry projects suit tanzanite beads best?

Tanzanite at Mohs 6.5–7 with distinct cleavage is best routed to low-impact pieces: earrings, pendants, lariats, and necklaces where beads aren't taking knocks. Avoid stacking bracelets and ring-adjacent designs where bead-on-bead or bead-on-hard-surface contact is constant. The cut sizes Dakota stocks lean small — 3mm and 4mm rounds, microfaceted rounds, and rondelles — which suits delicate strung work, multi-strand layering, and accent placement alongside gold-fill or sterling findings. Faceted cuts pull the most color saturation out of smaller beads; smooth rounds read quieter and pair well with pearl, moonstone, or labradorite for cool-palette work.
How do I care for finished pieces with tanzanite beads?

Clean with mild soap, lukewarm water, and a soft cloth — nothing more aggressive. Skip ultrasonic and steam cleaners; the cleavage planes in zoisite make tanzanite vulnerable to fracture from vibration and thermal shock. Avoid sudden temperature swings (don't move from hot car to cold AC), and keep finished pieces away from household chemicals, chlorine, and acidic cleaners. Store tanzanite strands separately from harder stones like quartz, topaz, or corundum that can abrade the surface. For customers, advise removing tanzanite jewelry before exercise, gardening, or anything involving impact.
What stones get confused with tanzanite in the bead trade?

Three come up most often. Iolite shares the violet-blue range but shows stronger pleochroism and is typically darker and less saturated; it's also significantly cheaper per strand. Blue sapphire beads run harder (Mohs 9) and hold a more pure blue without the violet flash. Generic zoisite — the parent mineral — is sold in green and pink varieties and shouldn't be marketed as tanzanite, which refers specifically to the blue-violet gem variety from the Merelani Hills. Dyed quartz and synthetic spinel sometimes appear at suspiciously low price points; genuine tanzanite carries a recognizable cost floor even in small bead sizes.
Why does color vary between tanzanite strands at the same size?

Tanzanite is pleochroic — it shows different colors (blue, violet, sometimes burgundy) along different crystal axes. How rough is oriented during cutting determines whether a finished bead reads more blue or more violet, and saturation depends on the depth of the bead and the quality of the source rough. Smaller beads (2–4mm) generally show lighter tone because less material means less color path; larger or faceted beads concentrate saturation. Strand-to-strand variation is normal and not a defect. If color matching across multiple strands matters for a production run, buy strands together from the same lot when possible.