Tandon Gems

Convert strand, gram and carat prices for tourmaline and sapphire rondelles

Anish Tandon, Founder, Tandon GemsPublished September 16, 2024· Reviewed September 5, 2026· 3 min read

This article is a reference guide. Some older product details and imagery have been omitted pending verification. Confirm the current strand, price and quantity with Anish before ordering.

Short answer

Use micro-rondelle reference weights, then do one quick calc. At 3 mm, tourmaline averages about 17 ct per 8 inches and sapphire about 20 ct per 8 inches. A 13 to 16 inch strand scales from those 8 inch baselines. Convert $/g to $/ct by dividing by 5, then multiply by carats per strand.

In short

  • 5 carats = 1 gram. Divide $/g by 5 to get $/ct.
  • 3 mm tourmaline: use 17 ct per 8 in, scaled for 13 to 16 in.
  • 3 mm sapphire: use 20 ct per 8 in, scaled for 13 to 16 in.
  • Per-strand from $/ct: price per ct times carats per strand.
  • Check strand length. Faceted rondelles often run 13 in from Jaipur.

How do I do the math on my phone?

We compare all quotes to per-strand using micro-rondelle reference weights. Identify the stone and strand length, then use the carats-per-strand below. From $/ct, multiply by carats per strand. From $/g, first divide by 5 to get $/ct, then multiply by carats per strand.

Anish here: I keep "5 = 1" in my notes, meaning 5 carats equals 1 gram. It speeds up every aisle.

  • Tourmaline 3 mm baseline: ~17 ct per 8 in
  • Sapphire 3 mm baseline: ~20 ct per 8 in

What carats are in a 13 to 16 inch micro-rondelle strand?

Use these working baselines for 3 mm faceted rondelles. They come from what we and our Jaipur cutters see in the trade, and they let you compare quotes fast.

For more on the materials themselves, our stone notes for tourmaline and sapphire are a good anchor when you're checking lots.

  • Tourmaline 3 mm: use 17 ct per 8 in, scaled to strand length
  • Sapphire 3 mm: use 20 ct per 8 in, scaled to strand length

How do I convert $ per carat to $ per strand?

Multiply the vendor's $/ct by the carats per strand from the ranges above. That gives you $/strand for a 13 to 16 inch micro-rondelle.

For a 16 in tag, use the high end. If it is between, split the difference.

How do I convert $ per gram to $ per strand?

First, turn $/g into $/ct. Divide the gram price by 5, since 5 carats equal 1 gram. Then multiply that $/ct by the strand's carats.

That result is the comparable $/strand. If the vendor will weigh the strand, great, but this method works when they will not.

What if the strand runs 2 to 6 mm or is graduated?

Graduated strands weigh more than a uniform 3 mm micro-rondelle. If you only need a quick compare, use the 3 mm ranges as a conservative estimate and note that the real $/strand may land higher.

When precision matters, ask for the strand weight or a scale. We see many faceted rondelles cut on 13 inch strings from Jaipur, which also affects total carats.

How many inches of beads do I need for bracelets and necklaces?

This helps you decide if one strand covers your project. Standard strand length from Jaipur is 13 to 16 inches. Faceted rondelles at 13 inches often cover a bracelet or choker, and two strands make a longer necklace.

On a 16 inch choker, the beaded run is about 14.5 inches. On an 18 inch necklace, it is about 16.5 inches. Knotting adds about 1 mm per knot.

  • Counts per 18 in: 4 mm about 104, 6 mm about 70
  • A 15 to 16 in strand of 6 mm rondelles has about 65 to 70 beads
  • A 15 to 16 in strand of 4 mm rondelles has about 95 to 100 beads
  • Counts for a 16 in choker: 6 mm about 61, 8 mm about 46

Where can I read more about bead shapes and planning?

Rondelles are the workhorse for strung designs. We note how they're measured and drilled on our rondelles page.

When you're comparing lots, keep the stone basics in mind. Our quick guides for tourmaline and sapphire cover hardness and use, which matters for bracelets and daily wear.

Common questions

Can I compare two strand quotes if one is 13 inches and the other is 16 inches?

Yes. Use the low end of the carat range for 13 inches and the high end for 16 inches, then multiply by $/ct or convert $/g to $/ct first.

Does $/g always convert cleanly for beads?

Yes, via weight. Divide $/g by 5 to get $/ct, then multiply by the strand's carats. Bead proportions vary, so confirm length and graduation when possible.

How do I handle mixed 2 to 3 mm micro strands?

Treat them as 3 mm for a quick compare. Use the micro carat ranges given, then adjust if the vendor can confirm an exact strand weight.

Will one 13 inch strand cover a bracelet?

Often yes. A 7.5 inch bracelet has about 6 inches of beads after findings, and 13 inches covers that easily with room for layout and matching.

Do I need to adjust for knotting between beads?

Yes. Knotting adds about 1 mm per knot, so you will use fewer beads per inch and can stretch a strand a bit farther.

Sources and checks

  1. Weights and Measures Conversion Chart - International Gem Society
  2. Weight Length Conversions - International Gem Society
  3. Bead and Necklace Size Charts - International Gem Society
  4. Your First Tucson Gem Show? Lessons From My First.... - Tucson Gem Show - Live!

Catalog details are reference information. Ask Anish to confirm the current strand, price and availability.

Want a strand like the ones in this post?

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