Dresser Trap Rock is a very hard basalt.  Therefore, many railroads use this stone for track ballast.  Any miniature model maker can use this product in its crushed form.  Choose from a range of sizes to fit the scale you model.  From ultra fine to coarse grades, Dresser Trap Rock will work with model railroads, farm dioramas, fairy gardens, doll houses, architect models or movie props.  The color is very distinct.  It can have hints of blue, red, or purple.  In contrast, in its crushed form, dark gray is the predominate color.  As a result, this rock works well in any miniature model.