Within Victorian society, like with Clothing and flowers there was a language associated with jewelry that could tell the public the age, status and wealth that could be attributed to a specific person. As such women would be a showcase for their husbands wealth. This language is shows a woman's lack of role following the death of her husband, as no widow is able to wear diamonds and jewelry is a part of the estate and thus was outside of the females control both before and after her husband’s death.
More information about Diamonds the laguages they spoke and the curses they carried here.
The diamonds used in those pieces of jewelry came predominantly from India due to the shallow diamond deposits within the land which allowed for mining to occur through pit mining instead of the deep tunnel mining that would have produced these jewels in other areas. This monopoly changed as Britain moved into Africa eventually establishing Rhodesia in the late 1800’s which held a large diamond deposit thus decreasing the necessity for Indian stones.
More information on Rhodesian diamond deposits here.
Within the Sherlock Holmes novel The Blue Carbuncle the dark histories that surround jewels is suggested following a specific blue gem transportation and theft. Within this piece homes specifically mentions the bloody histories that usually goes along with the purchase of diamonds and jewels from around the world, the specific gem in question having been found in southern China.
“When the commissionaire had gone, Holmes took up the stone and held it against the light. “It’s a bonny thing,” said he. “Just see how it glints and sparkles. Of course it is a nucleus and focus of crime. Every good stone is...In the larger and older jewels every facet may stand for a bloody deed. This stone is not yet twenty years old...In spite of its youth, it has already a sinister history. There have been two murders, a vitriol-throwing, a suicide, and several robberies brought about for the sake of this forty-grain weight of crystallised charcoal. Who would think that so pretty a toy would be a purveyor to the gallows and the prison?” (Page 4, full story here)