This post is also available in: polski
An abandoned Łomy quarry near the village of Lubiechowa, cut into a trachybasaltic Chmieleń hill (424 m), is among the best known mineralogical localities in the Kaczawskie Foothills. Thanks to its substantial dimensions, 150 m long and up to 30 m high walls, if offers a good insight into geological structure. One can recognize as many as seven superimposed lava flows of total thickness of 60 m. Some represent massive variants, with poorly developed columnar jointing, some are vesicular, and others are volcanic breccias consisting of lava fragments and pyroclastic materials. Vesicular varieties warrant special attention. Vesicle filling is fairly common at Łomy and may be complete or partial. If the latter is the case, one deals with geodes. In certain places vesicles are arranged parallel to one another, indicating the direction of lava flow before it solidified. Typical fillings, all due to precipitation from hydrothermal fluids circulating within the rock in the late stages of volcanic activity, include milk quartz, smoky quartz, zeolite, amethyst, barite and calcite, usually in the form of druzes. Most geodes are no bigger than 2 cm, but large specimens up to 30 cm can be found. Voids are filled by ribbon agates, with milk quartz or amethyst in the central part. The quarry is maintained as a tourist site and access from the village is signposted.