[NEO]

http://www.thepotteries.org/mark/reg.htm#1842

What is a Diamond Mark?

During the period 1842-1883 the British Patent Office issued a diamond mark along with the registration number when a design was registered.
As well as showing that the design had been registered, diamond mark offered the buyer the reassurance of knowing an item was of British design. It also assured the person registering the design a degree of protection from copying. The protection was dependent on the type of material and the class in which the product was placed.
The mark was created to identify the type of material used (known as the class), how many items were included, (sometimes known as bundles or packages, and the date of registration.
Note that the registration number does not form part of the mark.
The centre is occupied by the abbreviation Rd signifying that this is a Patent Office mark standing for Registered Design.

[Алесио]

How to understand the mark?

1) What 'class' is the material?

The Roman numeral at the top of the diamond indicated the 'class' or type of material used - for example III was for glass ware and IV was for clay ware.

[Алесио]

2) What year range is the mark from?

There are two ranges of year codes; 1842-1867 & 1868-1883. At first glance they look the same but if you look closely you can see that some have a number at the right hand corner and some have a letter.

If there is a number at the right hand corner of the diamond then it is in the 1842-1867 range

If there is a letter at the right hand corner of the diamond then it is in the 1868-1883 range

number at the right hand corner of the diamond
1842-1867 range

[Алесио]

letter at the right hand corner of the diamond
1868-1883 range

[Алесио]

3) Understanding marks 1842-1867

First of all make sure there is a number in the right hand corner as shown below:-
If there is a letter then the mark is 1868-1883

[Алесио]

You can ignore the number at the bottom of the diamond - this tells us how many items were included in the registration, (sometimes known as bundles or packages).
From the other numbers and letters we can work out the date of the registration.

Day - Right hand corner - this is self explanatory

Month - Left hand corner - this is worked out from the code below:-Month letter Month Month letter Month
A December H April
B October I July
C January K November
D September M June
E May R August
G February W March




Year - Top of the diamond - this is worked out from the code below (they are listed in alphabetical order):-Year codes for 1842 - 1867Year codes Year codes Year codes
A 1845 J 1854 S 1849
B 1858 K 1857 T 1867
C 1844 L 1856 U 1848
D 1852 M 1859 V 1850
E 1855 N 1864 W 1865
F 1847 O 1862 X 1842
G 1863 P 1851 Y 1853
H 1843 Q 1866 Z 1860
I 1846 R 1861



Exception Notes:
In 1857 the letter R was used during 1-19 September, and during 1860 the letter K was used for December.

registration date for this mark:
27th April (H) 1847 (F)

[Алесио]

just to prove it works.....!
Jones & Walley put both the date and
the registration diamond to give the following:-
13th May (E) 1843 (H)

[Алесио]

4) Understanding marks 1868-1883

First of all make sure there is a letter in the right hand corner as shown below:-
If there is a number then the mark is 1842-1867

[Алесио]

You can ignore the number at the right hand corner of the diamond - this tells us how many items were included in the registration, (sometimes known as bundles or packages).
From the other numbers and letters we can work out the date of the registration.

Day - Top of the diamond - this is self explanatory

Month - Bottom of the diamond - this is worked out from the code below:-Month letter Month Month letter Month
A December H April
B October I July
C January K November
D September M June
E May R August
G February W March




Year - Right hand corner of the diamond - this is worked out from the code below (they are listed in alphabetical order):-Year codes for 1868 - 1883Year codes Year codes
A 1871 L 1882
C 1870 P 1877
D 1878 S 1875
E 1881 U 1874
F 1873 V 1876
H 1869 X 1868
I 1872 Y 1879
J 1880
K 1883



Exception notes:
From 1-6 March 1878, W was used for the year in place of D; and G was used for the month in place of W.

registration date for this mark:
29th September (D) 1879 (Y)

[Алесио]

5) This year table is in chronological order -to help in identifying possible exceptions as shown below:1842 - 1867 and 1868 - 1883Year codes Year codes Year codes Year codes
1842 X 1855 E 1868 X 1881 E
1843 H 1856 L 1869 H 1882 L
1844 C 1857 K 1870 C 1883 K
1845 A 1858 B 1871 A
1846 I 1859 M 1872 I
1847 F 1860 Z 1873 F
1848 U 1861 R 1874 U
1849 S 1862 O 1875 S
1850 V 1863 G 1876 V
1851 P 1864 N 1877 P
1852 D 1865 W 1878 D
1853 Y 1866 Q 1879 Y
1854 J 1867 T 1880 J





Exception Notes:
In 1857 the letter R was used during 1-19 September, and during 1860 the letter K was used for December. From 1-6 March 1878, W was used for the year in place of D; and G was used for the month in place of W.