www.925-1000.com

Margot pieces are usually signed Margot de Taxco so MT wouldn't be trying to be her, her full name was Margot Van Voorhies Carr. MT is probably the artisans initials but it's not noted in the hallmark book.

It's definitely Shube's.

Del Rio, 0.925, Hecho en Mexico.
The stones are glass.

Mexico IDM 925. There is no info on IDM in the hallmark book which is more common than having info.

925 is a worldwide sterling standard.

I've had jewelry with a pheasant mark but not marked El Faisan, is that still his mark?

The book doesn't give that kind of info and is 10 years old so not very current.

The hallmark book says Philip Iule-Zuni/SanFelipe, is a silversmith/lapidarist who specializes in cast silver pieces with simple inlay, learned from his parents.

The DF is for Distrito Federal aka Mexico City. No eagle mark dates it prior to 1948. The mark is mentioned in the hallmark book but with no further info. It's more common to not be able to find a name for a maker than it is to find one.

The HS is for Harry Sandoval, the LB mark is for the Les Baker shop.

There are 2 SH marks in the hallmark book but neither has a name known.
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It's not Mexican, Mex pieces are marked Mexico in some way 99.99% of the time, definitely not Melendez, not even close to his mark.
It looks to be Southwest or possibly Native American.

Depending on the conditions a piece can turn black in a very short time. It means nothing in relation to age, brand new pieces can turn black quickly.
Unless a jeweler works a lot with old and estate pieces they aren't usually very good at ID'ing anything but new pieces.

A friend of mine had a similar bracelet she dated 50's-60's.

That's the eagle head mark found on a lot of tourist items. It isn't the eagle mark found on silver that is a full body bird with a number in the center. This is made of alpaca or another non-silver metal. You'll often find them with a false 925/sterling mark as well. It may not really be from Taxco...

The mark on the clip is a manufacturer's mark, for the clip only. I've seen the name before but don't remember it, it has nothing to do with the earrings themselves.
The mark on the earrings almost looks Middle Eastern.

The flower set dates from 1979-now. It's a fairly common design done by many unknown artisans. The earrings date prior to 1948, maker also unknown. It's more common to not find the maker than it is to be able to find it. Only famous names seem to affect the value of a piece and their marks are prett...

Try taking the pic through a magnifying glass and in stronger light. Those tiny marks can be a real pain.

It's still the Shube mark as discussed in your earlier post. The stone is Turquoise, not Torquoise.
http://www.925-1000.com/forum/viewtopic.php?f=14&t=15070&p=53119&hilit=shube#p53119

There's too much glare to see anything but 925.