Both gold and a lot of gemstones have a great many uses in industry and electronics, garnet for example is used in water jet cutting and if you have a smart watch there is a good chance its touch screen is made of sapphire
And then there is the sheer amount of gold we use in plating soooo many of our printed circuit boards and connectors
With the exception of gold, all of your above examples are usually either abundant and cheap (garnet), or are cheaper and better when made in a lab. For example: Sapphire is just aluminum oxide – no one is cutting phone screens from mined gems. And lab made diamonds are pennies on the dollar.
Both gold and a lot of gemstones have a great many uses in industry and electronics, garnet for example is used in water jet cutting and if you have a smart watch there is a good chance its touch screen is made of sapphire
And then there is the sheer amount of gold we use in plating soooo many of our printed circuit boards and connectors
With the exception of gold, all of your above examples are usually either abundant and cheap (garnet), or are cheaper and better when made in a lab. For example: Sapphire is just aluminum oxide – no one is cutting phone screens from mined gems. And lab made diamonds are pennies on the dollar.