2 grams and measuring 72x66x10mm

Origin: Mined in Bou Beker

most of these fragments under 20 grams

Austria displays its excellent prismatic crystals which are considered  world class for this species

Calcite on Calcite on Matrix | Crystal Cluster 55.52g | Oskaloosa, Mahaska County, Iowa, USA | SO24 NWA 250 2 grams and measuring 72x66x10mmThis is a natural cluster formation of calcite on calcite crystals or two variations of the mineral found in a cracked concretion in a coal mine in Oskaloosa, Mahaska County, Iowa, USA. It is a specimen consisting of two types of calcite on matrix. The first type is a coating of iridescent, dark calcite on the matrix. The second type are white crystals of calcite. It is in good condition. Would be a nice addition to any new or existing collection.