The closed quarry Łomy near Lubiechowa, located on the Chmieleń hill (424 m) built of Permian trachybasalts, is one of the most well-known mineralogical sites in the Kaczawskie Foothills. Due to its large size, with a length of 150 m and wall heights of up to 30 m, it allows for insight into the geological structure. It consists of seven lava flows with a total thickness of about 60 m, including more massive variations exhibiting weak columnar jointing, vesicular varieties, and volcanic breccias composed of fragments of lava and pyroclastic material.
Particular attention is drawn to vesicular varieties, also known as amygdules, when gas bubbles have been secondarily filled. The filling of vesicles is quite common in the trachybasalts of Łomy and can be complete, forming amygdules, or partial, in which case they are referred to as geodes. In some places, they align linearly, indicating the direction of lava flow before solidification. Typical fillings, formed by the crystallization from hot hydrothermal solutions circulating in the rock during the late stages of volcanic activity, include milky quartz, smoky quartz, zeolite, amethyst, barite, and calcite, usually in the form of distinct crystal brushes.
Most geodes do not exceed 2 cm in length, but large specimens up to 30 cm are also encountered. The amygdules are filled with banded agate, sometimes with milky quartz or amethyst in the central part. The quarry has been partially developed, and access from the Lubiechowa side is marked.
Description: Piotr Migoń
