Polished Tiger Iron slab TI276 oldest agate in the world 100 mm x 75 mm

100 mm x 75 mm x 13 mm thick & weighs 233 grams

Porphyry is a general term that is used rather loosely for  igneous rocks which contain relatively large isolated crystals set in a fine-grained groundmass

Prase is a chrome-rich chert

Dimensions at widest points approximately 115 mm x 75 mm x 10 mm thick

Weighs 344 grams

Polished Tiger Iron slab TI276 oldest agate in the world 100 mm x 75 mmTI276 Tiger Iron slab, polished on one side . Dimensions at widest points approximately 170 mm x 75 mm wide x 9 mm thick. Weighs: 272 grams From the Cleaverville Formation, Ord Ranges near Port Hedland, Western Australia. Age is over 3 billion years. , Tiger iron is a banded iron formation (BIF) or jaspilite that has alternating layers of black and brown hematite magnetite, red jasper and chatoyant golden tiger eye.