🔎 UNIDENTIFIED iridium / osmiridium?

[detectorFRED]

Need Help Identifying Unusual Stone Found in Pennsylvania

I found this unusual specimen while excavating/preparing ground for a concrete pad in Pennsylvania. It was buried in the soil/subsurface — not found along a railroad bed.

Photos attached.

What caught my attention:

• Silver-gray fibrous/radiating texture
• Numerous vesicles/voids throughout
• Some reflective/metallic-looking areas in sunlight
• Porous but somewhat dense/heavy for size
• Very unusual texture compared to the surrounding rock
• The Sample Weighs 36 grams
  
  
  
  
  
  
  
  

Some possibilities I’ve considered:

• Industrial smelter slag
• Furnace clinker
• Fossiliferous limestone/coral
• Iron-rich concretion
• Nickel/copper slag
• Possibly something containing platinum group metals (iridium/osmiridium?) — though I understand that would be extremely uncommon

I’m not claiming it is valuable; I’m simply trying to identify it correctly before doing destructive testing.

Planned tests:

 

[russau]

Good idea ! Look before you jump is a good plan of attack before any destructive actions on your part !

 

[fuss]

Before any destructive tests try a streak test and certainly a hardness test. Can your fingernail scratch it? The vesicles scream slag but if it weren't for them the texture would make me think an Amphibole mineral of some kind.

 

[blauer]

Before any destructive tests try a streak test and certainly a hardness test. Can your fingernail scratch it? The vesicles scream slag but if it weren't for them the texture would make me think an Amphibole mineral of some kind.

Guess not.