Black Amber, Jet and Coal - What’s the Difference?
By Sonia Acone
On your crystal journey, you may have come across some rather confusing information. One of these issues concerns Black Amber and its relation to Jet. Are they one and the same? What is Black Amber anyway? What is the difference, if any, between Jet, Black Amber and Coal?
First things first - Black Amber is neither Amber nor Jet. It is just a trade name of sorts used for Jet because both Amber and Jet give off an electric charge when rubbed.
Amberis essentially fossilized tree resin.
Jetis fossilized tree wood (Note: Petrified Wood is also fossilized wood, but is much heavier due to the fact that the wood has, over time, turned into crystal). Jet is very light weight and has a hardness of 2.5 on the Mohs scale. It has an amorphous system and is considered to be a mineraloid. Jet is a variety of coal called Lignite, is warm to the touch and is a dull, waxy black; however, when polished, Jet has a high sheen to it.
Coalis a sedimentary rock containing fossilized plants. It is cold to the touch and very brittle. Coal is normally quite glassy in appearance.
One way to tell the difference between Jet and Coal is to do a Streak Test: Take a piece of unglazed porcelain (the back of a ceramic tile, for instance), and rub your Jet or Coal on the tile - if it leaves a brown streak, it is Jet; a black streak is Coal. Another test is the Red Hot Needle Test (click here: http://jmfelton.com/jetid1.htm to see how to perform this test).
I hope this gets rid of some of the confusion regarding Jet, Coal and Black Amber.