Heulandite

Colourless, semi-transparent crystals of the rare zeolite Heulandite richly invest a highly vuggy, naturally etched Calcite matrix.  It is now recognised that Heulandite from St. Andreasberg in the Harz Mountains of Lower Saxony, Germany, is the species Heulandite-Ca.  Crystals are typically 2 to 3 mm long and scattered amongst these are euhedral translucent cream Calcite crystals to about 1 cm.

Ex. the Mineral Collection of Archduke Stephan Franz Viktor of Hungary (1817 to 1867), with a historic Archduke (Erzherzog) Stephan label incorporating his coat of arms.  This smaller label measures 8.6 x 4.7 cm; it is complete (untrimmed) and is numbered 239/10, with this same number glued to the specimen’s side together with a Carl Rumpff label, dated 1889.  This smaller sized Archduke label is in very good condition, with very minor light foxing and one vertical crease.