Steel Ring Support Plate, 3.75" Diameter Geology Specimen Collections_Rock & Mineral Collections mounted on a swivel boss

mounted on a swivel boss head fitting 18mm rods for secure angular placement on retort stands

a 75mm-aperture double-concave glass lens at 100mm focal length spreads light through optically worked surfaces and ground polished edges

Red-coated Alnico cylindrical pair at 50 x 10mm

3 ratio giving fast convergence with moderate working distance for image-formation work

Long-focal 50mm concave glass mirror at 300mm focal length and ~1

Steel Ring Support Plate, 3.75" Diameter Geology Specimen Collections_Rock & Mineral Collections mounted on a swivel bossFlat 3. 75 inch steel platform on a 6 inch stem, this ring stand support plate gives crucibles, heating apparatus, and small labware a stable flat surface during retort assemblies.