I will write a few more quick notes on pigments and then, on to a new subject.
Umbers are iron oxides dug from the earth. Originally they came from the Umbria region of Italy, but are found all over the world. Raw umber is a slightly greenish, cool brown color. Burnt umber has been heated until it has a warm slightly reddish color. Both contain manganese, so they are poisonous. That's not something you would expect in an earth color. I don't use either of these although they are popular and inexpensive colors. I have so many colors on my palette that not everything makes the cut. I do sometimes play around with the raw umber, but I generally feel that it is too dirty. It also lures students into adding it to all of their shadows, like they do with black, which is the cause of a good deal of unhappiness and disappointing color. Umbers also seem to cause "drying in" where parts of a painting will go matte and distract from the otherwise glossy surface. I recommend that unless you are a very experienced painter, umbers shouldn't be on your palette, at least not outside. It is better to mix your browns, as you will get more life and variation in your notes.
Indian yellow, is a synthetic color, usually diarylide . It has a golden yellow color and is transparent. According to its manufacturers it is permanent. Diarylide is also used to make Permanent yellow. I don't use this color.
Dioxazine violet is a very powerful semitransparent purple color. I find it too powerful, it is like a purple pthalocyanine. It will stain the hair on your brush and I find it difficult to keep in check. I like a cobalt violet, but of course that is expensive. I think for most of you, mixing your violets from ultramarine and Alizirin crimson permanent is the best way to go. Frequently manufacturers mix Dioxazine with other less assertive pigments and give it a fanciful name, like "organ meats hue"or "wilted spurge". If you experiment with those you may find that one suits your purposes. If you are married to a thoracic surgeon, buy Old Holland cobalt violet in the big tube.
Paynes gray, blue black, and Indigo are all blacks to which some blue pigment has been added. They are as easily mixed as bought. However they are sometimes fun to use in an earth color palette. Indigo is now a synthetic color, that was once made from a plant grown as a dyestuff. It is the color of new blue jeans and was used extensively by Edward Seago, hence my interest in that color.