Buying semi-precious beads – a guide to size and shape

If you’re new to working with semi-precious gemstone beads and you want to start buying them you should bear in mind a couple of things regarding their size and shape.

Does size matter?

Common sizes for round beads.

Gemstone beads are measured in millimetres. Round beads are measured by their diameter (the widest part of the bead), so you will often see items listed as 4mm or 10mm. Easy enough, right?

It gets more complicated because it’s common to expect a tolerance of up to half a millimetre plus or minus on your beads. It means those 4mm beads could actually be 3.5mm. Anyone familiar with buying semi-precious beads will no doubt have encountered this.

Cutting and shaping stones is notoriously difficult – some stones are softer than others and therefore easier to shape while others are much harder to cut, so the finished product does vary. But do you need to worry about this?

Most beaders are aware of the tolerance and can work around it. But you might get stuck when you try to string a small 4mm round with a large 4mm and discover an entire millimetre difference. So if size is critical to your design you should check with your supplier first.

Temporarily strung or loose beads?

You will often see beads for sale individually, in packs or on strings. What’s the difference?

Typically semi-precious beads are cut, polished and then put on a temporary string by the factory before being sold on. The standard length of these strands ranges from 38 – 40 cm.

Some retailers will break these strands up and sell the beads individually, while others (like BeadShopUK) will sell them by strand.  

Generally speaking, it’s cheaper to buy your items on a temporary string rather than individually. It’s the same principle of buying bulk that you encounter whenever you go to the supermarket.

You can calculate how many beads you can expect based on the diameter of the bead and the length of the strand. For example, a 40cm strand of 10mm beads will have 40 beads (just divide the strand length by the diameter of the beads)

However, because beads do vary in size, and the strand length can vary, you should use this calculation as an estimate. If you need an exact number of beads for your deign it’s best once again to check with your supplier.

Tip:  To quickly measure the size of your beads, count ten beads and hold them against a ruler - 10 x 4mm = 4cm, 10 x 6mm = 6cm etc.

10 x 8mm Carnelian Beads

Shapes or rounds?

There are all kinds of shapes on the market. Do you want round beads as spacers, or maybe some cubes, rectangles or ovals?

A variety of semi-precious stones and shapes.

Shaped beads are becoming increasingly popular with jewellery designers and the availability of shaped gemstone beads is increasing. Shapes can add individuality to a design but you should bear in mind that you will have to use spacer beads so that the shaped bead hangs properly.

That’s where the fun comes in – will you use small round spacers of the same type of stone? Or are you going to find a contrasting colour from another variety? The designs are endless!

At the end of the day it’s all about experimentation, so find the size and shape that works for you and have fun trying out your designs.

Hopefully this brief article will give you an overview of what you can expect when buying semi-precious gemstone beads, but if you have any questions or comments, please feel free to get in contact.