ClipArt ETC
This figure reproduces a combination of orthorhombic forms observed on crystals of aluminum orthosilicate, or Andalusite: (a), (b), (c), (m), (l), (n), (r), (p), (s), and (k).

Andalusite

This figure reproduces a combination of orthorhombic forms observed on crystals of aluminum orthosilicate,…

"Plan and Transverse Section of Sir William Thomson's Compass-card. B, Corrector for quadrantal error; C, Box for corrector; a, Aluminium boss; b, Central cap of sapphire; c, Cords connecting rim and boss; d, Magnets; e, Threads connecting magnets; f, Aluminium rim; f, Cords supporting magnets; g,g', Knife edges for gimbals." — Encyclopedia Britannica, 1893

Compass Card

"Plan and Transverse Section of Sir William Thomson's Compass-card. B, Corrector for quadrantal error;…

Mechanical drawing convention for identifying Aluminum. Using conventionalized patterns to identify materials is called section lining.

Aluminum

Mechanical drawing convention for identifying Aluminum. Using conventionalized patterns to identify…

Striation of crystal planes may be produced by repeated polysynthetic twinning. This is well illustrated in the case of the triclinic feldspar, Albite. The twinning plane here is the brachypinacoid, and the contact of a large number of fine lamellæ, alternately in twinning position, would evidently produce a striation on the basal plane parallel to the brachydiagonal axis

Striation of Crystal Planes

Striation of crystal planes may be produced by repeated polysynthetic twinning. This is well illustrated…