Below are some useful charts for jewelry makers or for jewelry shoppers.  Scroll down for charts of the Moh’s scale, a bead chart, a necklace length chart and a birthstone chart.


Moh’s scale shows the relative hardness of various gems and minerals. Each stone will scratch the stones below it, but not the stones above it on the scale.  All gems have a Moh’s number.  If a stone is listed as 6.5 for example, its hardness  will be about halfway between that of feldspar and quartz.  The Moh’s scale is useful for judging the durability of a stone for jewelry use and is also a useful tool in identifying an unknown specimen.

10 Diamond
9 Corundum (sapphire)
8 Topaz
7 Quartz
6 Feldspar
5 Apatite
4 Fluorite
3 Calcite
2 Gypsum
1 Talc


Bead Chart

Another of the useful charts for jewelry makers. it is used to determine how many beads you’ll need for a particular jewelry project.

Bead Size Beads per Inch Beads per 16”
2 mm 12.5 200
3 mm 8.3 133
4 mm 6.25 100
5 mm 5 80
6 mm 4.2 66
7 mm 3.6 57
8 mm 3.13 50
10 mm 2.5 40
12 mm 2.1 33

Necklace Lengths
Standard Necklace lengths These are the terms commonly used for various lengths of  necklaces

Choker 16 inches
Princess 18 inches
 Matinee 20-24 inches
Opera 28-32 inches
Rope >32 inches



There are several versions of the list of birthstones assigned to each month, but these are the two most common:




January Garnet Garnet
February Amethyst Amethyst
March Aquamarine Bloodstone
April Diamond Diamond
May Emerald Emerald
June Alexandrite Pearl
July Ruby Ruby
August Peridot Sardonyx
September  Sapphire Sapphire
October Rose Zircon Tourmaline or Opal
November Golden Topaz Topaz
December Blue Zircon Turquoise or Lapis