Australian Goldfields Miners Brooch by Larard Brothers, Melbourne

• Carat - A carat (abbreviated "ct") is a unit of measurement used to describe the weight of a diamond or other gemstone, and separately is a unit of measurement used to describe the weight of precious metals such as gold,.
  
  For gemstones, one carat is equal to 0.2 grams or 200 milligrams. The weight of a diamond is one of the Four Cs (along with cut, colour, and clarity) that are used to determine a diamond's value.
  
  It is important to note that a diamond's weight does not necessarily correspond to its size. A diamond's cut, which affects how well it reflects light, can make a diamond of a lower weight appear larger than a diamond of a higher weight. Additionally, the carat is not the only factor to determine the value of a diamond, other factors such as clarity, colour and cut are important too.
  
  In the gold industry, the purity of gold is measured in carats (abbreviated "ct"), with 24 karats being pure gold and lower carat numbers indicating a lower purity level. So, for example, 18 carat gold is 18/24 or 75% pure gold, and 12 carat gold is 12/24 or 50% pure gold.
• Circa - A Latin term meaning 'about', often used in the antique trade to give an approximate date for the piece, usually considered to be five years on either side of the circa year. Thus, circa 1900 means the piece was made about 1900, probably between 1895 and 1905. The expression is sometimes abbreviated to c.1900.
• Registered Numbers - Between 1842 and 1883, a diamond- shaped mark was used to identify items as British-made, which classified the item according to the material from which it was manufactured, as well as the date of registration. This system was discontinued in 1884 when a numbering system was introduced.
  
  Design registration is for "what and item looks like", and is not a patent ("how something works") or trade mark ("what it is called").
  
  The registered number is usually on an under-surface of an object (on the base of ceramics) and oftern shown as "Rd. No. 99999", sometimes surrounded by a rectangular box.
  
  The table below lists the year, and the first registered number for that year:
  
  1884 1
  
  1885 18,993
  
  1886 39,547
  
  1887 61,207
  
  1888 87,266
  
  1889 111,664
  
  1890 140,481
  
  1891 160,613
  
  1892 183,259
  
  1893 203,348
  
  1894 223,861
  
  1895 244,726
  
  1896 266,237
  
  1897 288,848
  
  1898 309,956
  
  1899 328,527
  
  1900 349,120
  
  1901 367,628
  
  1902 380,979
  
  1903 401,944
  
  1904 422,489
  
  1905 428,004
  
  1906 469,160
  
  1907 486,464
  
  1908 516,375
  
  1909 533,561
  
  1910 546,084
  
  1911 561,570
  
  1912 585,707
  
  1913 608,541
  
  1914 627,887
  
  1915 642,613
  
  1916 651,079
  
  1917 655,001
  
  1918 662,576
  
  1919 665,728
  
  1920 664,869
  
  1921 676,491
  
  1922 685,412
  
  1923 691,571
  
  1924 695,944
  
  1925 705,943
  
  1926 716,386
  
  1927 723,430
  
  1928 725,899
  
  1929 740,459
  
  1930 741,336
  
  1931 757,945
  
  1932 767,110

This item has been included into following indexes:

• brooches, set with - goldfields nuggets 143
• Golden Fleece (Australia) - advertising and garagenalia 31
• Larard & Son (Australia) - jewellery 26
• miners / mining / goldfields - jewellery, brooches, Australian 282