Garnet or Agat ?

[Cariboo5]

Not sure exactly which one this is.. Is there a sure fire way to tell which is which. Thanks to all in advance...

 

[Bajahunter]

Looks like a piece of carnelian, a type of chalcedony. Agate is also a type of chalcedony. In some places the word agate is used to describe all types of chalcedony.
You can tell the difference by their form. The lumps on your piece are called mammilarian form and are very common form for chalcedony to take. Garnet will have a very distinct crystal shape. Chalcedony should leave a white streak on a piece of porcelain tile, garnet should be colorless.
Either way it is a semiprecious stone. Nice find.

 

[mamabear]

I agree, carnelian. nice piece.

 

[CoinFetcher]

Botroydial (turtle back) Carnelian (red Agate)

 

[Cariboo5]

I would not have guessed Carnelian. Now that I know what these are thanks to you, it makes it alot more interesting and enjoyable as we are finding several of these on the claim in different shapes and sizes...