Gravel areas where there is little traffic. Globally, far more roads are surfaced with gravel than with concrete or tarmac; Russia alone has over of gravel roads. Both sand and small gravel are also important for the manufacture of concrete. Large gravel deposits are a common geological feature, being formed as a result of the weathering and erosion of rocks. The action of rivers and waves tends to pile up gravel in large accumulations. This can sometimes result in gravel becoming compacted and lithified into the sedimentary rock called conglomerate. Where natural gravel deposits are insufficient for human purposes, gravel is
Granular cell tumor Granular cell tumor Granular cell tumor is a tumor that can develop on any skin or mucosal surface, but occurs on the tongue 40% of the time. It is also known as Abrikossoff's tumor, Granular cell myoblastoma, Granular cell nerve sheath tumor, and Granular cell schwannoma.)Granular cell tumors (GCTs) affect females more often than males. Granular cell tumors show similarity to neural tissue, as can be demonstrated by immunohistochemistry and ultrastructural evidence using electron microscopy. Multiple granular cell tumors may seen in the context of "LEOPARD syndrome", due to a mutation in the "PTPN11 gene". These tumors on occasion may