Part 3 of 6, I figured a lot of you would enjoy this.
" Since 1937, both of these lists have changed. In 1957, the Jewellery Industry Council of America amended the American list by adding alexandrite as a birthstone for June and citrine as a birthstone for November, while modifying October to cite pink tourmaline as the specific variety of tourmaline to be used as an October birthstone. At some point in the 20th century, sardonyx was removed from the American list and zircon was added as a birthstone for December. The American Gem Trade Association added tanzanite to the American list in 2002 as a birthstone for December, and in 2016 added spinel to the list as a birthstone for August in collaboration with the Jewellers of America (formerly the National Association of Jewellers). The inclusion of stones labeled as ‘alternative birthstones’ on this list also eventually changed, and all stones used in the American list are now considered ‘official’. The list used in Britain by the National Association of Goldsmiths has received modifications since its original development as well."