This looked like a good link. It's one of the better ones I've been able to find. But I've always found discrepancies when it comes to 'jet'.
So what do I do? Hit Wiki. (It's damn got everything.) I remember before, a friend and I debated it. Coal or fossilized wood?
"Jet is a geological material and is considered to be a minor gemstone. Jet is not considered a true mineral, but rather a mineraloid as it has an organic origin, being derived from decaying wood under extreme pressure.
The English word-name "jet" derives from the French word for the same material: jaiet. Jet is either black or dark brown, but may contain pyrite inclusions, which are of brassy color and metallic lustre. The adjective jet-black is better-known perhaps than the substance from which the descriptive phrase derives.
Jet is a product of high pressure decomposition of wood from millions of years ago, commonly the wood of trees of the Araucariaceae family. Jet is found in two forms, hard and soft. Hard jet is the result of the carbon compression and salt water; soft jet is the result of the carbon compression and fresh water. Jet is easily polished and is used in manufacturing jewellery, according to the Whitby Museum, dating from 10,000 BC in parts of contemporary Germany. The oldest jet jewellery was found in Asturias, Spain, dating from 17,000 BC.
Jet as a gem material was highly popular during the reign of Queen Victoria, during which the Queen wore Whitby jet as part of her mourning dress. Jet was popular for mourning jewellery in the 19th century because of its sombre color and modest appearance, and it has been traditionally fashioned into rosaries for monks. In the United States, long necklaces of jet beads were very popular during the 1920s, or Roaring Twenties, when women and young flappers would wear multiple strands of jet beads stretching from the neckline to the waistline. In these necklaces, the jet was strung using heavy cotton thread; small knots were made on either side of each bead to keep the beads spaced evenly, much in the same way that fine pearl necklaces are made. Jet has also been known as black amber, as it may induce an electric charge like that of amber when rubbed. Powdered jet added to water or wine was believed to have medicinal powers."
What I think is neat is that it has the electrical charge thingie.
And of course, Wiki's take on Amber:
""Amber is fossil tree resin, which is appreciated for its color and beauty. Good quality amber is used for the manufacture of ornamental objects and jewelry. Although not mineralized, it is often classified as a gemstone.
A common misconception is that amber is made of tree sap; it is not. Sap is the fluid that circulates through a plant's vascular system, while resin is the semi-solid amorphous organic substance secreted in pockets and canals through epithelial cells of the plant.
Because it used to be soft and sticky tree resin, amber can sometimes contain insects and even small vertebrates.
Semi-fossilized resin or sub-fossil amber is known as copal.
Amber occurs in a range of different colors. As well as the usual yellow-orange-brown that is associated with the color "amber", amber itself can range from a whitish color through a pale lemon yellow, to brown and almost black. Other more uncommon colors include red amber (sometimes known as "cherry amber"), green amber, and even blue amber, which is rare and highly sought after.
A lot of the most highly-prized amber is transparent, in contrast to the very common cloudy amber and opaque amber. Opaque amber contains numerous minute bubbles. This kind of amber is known as "bastard amber", even though it is in fact true amber."
But be wary, kids, of 'reconstituted amber' sold as the real McCoy:
"Reconstituted amber is the most difficult, sometimes fooling experts; it is, after all, noting more than amber chips made into a large piece with a “filler”, usually melted copal or something similar."
Anywhozzle, I would file away the 'electrical charge' as part of the value of the 'stones' to more traditional witches, but I make no assumptions.
I had to restring mine recently, and not having enough (poor lost beads! they are quite expensive!), I actually restrung it with magnetic hematite. Wonder what that's going to do.