Sapphire?

[dreamsofgold]

I pulled this out of a creek in south eastern Pennsylvania. Not sure what it is

 

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[Eu_citzen]

Can it scratch a quartz?

 

[BurntBear]

It's really hard to distinguish from the photos, but the color doesn't seem right to me.

 

[Jim in Idaho]

Sapphire, being corundum, one of the hardest known materials, usually isn't that eroded when found.
Jim

 

[dreamsofgold]

I don't know if this info will help identify or not but I found this on a fast moving creek located on the Martic Thrust here in Lancaster PA. Rocks nearby include: Granite, Quartzite, Chrome Ore, Iron Ore Marble and a variety of metamorphic rocks.

 

[dreamsofgold]

I found this at the same location. I struggled to break a small piece off with a 20lb sledge hammer so there are definitely some super hard rocks in this vicinity.

 

[BurntBear]

Hey dreams, I actually grew up just south of you across the Maryland line. Some of the finest granite I've ever seen is from that area and you're absolutely correct on the rock formations around you.

Check the Mindat link here for a detailed list.

Mindat for Cecil Co.

 

[Jim in Idaho]

I found this at the same location. I struggled to break a small piece off with a 20lb sledge hammer so there are definitely some super hard rocks in this vicinity. View attachment 1028061

The hardness is not about how hard it is to break....it's about how hard it is to wear. Diamond is the hardest natural substance, and is very easy to break. But, diamonds are so resistant to wear that they will travel hundreds of miles in a stream, and still have fairly sharp corners. Same with corundum, but not as much.
Jim

 

[JLeonhardy]

If you have a lot of serpentine, actinolite and other related stones in your area, my guess would be crocodolite -- a blue variation of actinolite/serpentine. It's a beauty!

 

[BurntBear]

I found this at the same location. I struggled to break a small piece off with a 20lb sledge hammer so there are definitely some super hard rocks in this vicinity. View attachment 1028061

The white pieces look like Plagioclase Feldspar var. "Albite".