Please help identify this plum

Hello all,

Thanks in advance for helping me figuring out this plum.

This tree is about 8 - 10 years old and at a friends place.  It is a canopied tree with about 12 feet of width. And may be about 10 ft tall.

They think it is a Green gage plum but the fruit colors are different than a typical Green gage. The skin is slightly thick then a regular store plum. Mostly sweet with notes of tartness.

In colorado, Zone 6 now.

It feels like a free stone. the fruit is not too clingy to the pit. Please see pics.

Thanks again.

Welcome to Permies Ma Kavu.
It is not like any greengage I have seen.  They usually have a bright green skin with pale yellow to green flesh.
Greengages, and other gages are strictly not a true plum, being a European cultivar of Japanese plums.
The plums you show could be santarosa or mirabel.
Cheers

Thank you, Paul.

From the research I have done, I would agree with you.

I wanted to see if anybody else experienced this kind of plum before  

Actually some of the seedling crosses with the original green gauge on this old homestead have those characteristics.

That is so interesting.