Stalactitical Calcedony Enlarge
April 1 1809 Publish’d by Jas Sowerby London
British Mineralogy
Silex Quartzum, var. Stalactites

Stalactitical Calcedony

  • Div. 2. Imitative.
  • Var. Stalactitical.
  • Syn. Quartz Agathe. Haüy, 2. 424.

Trevascus in Cornwall has afforded the finest examples of this peculiar Stalactitical Calcedouy. My liberal friends the Hon. Charles Greville, Philip Rashleigh, Esq. and Mr. Riehard Phillips can show truly magnificent specimens; above a foot in diameter in some parts, and of every varied form, including the following examples.

The upper figure serves to express the more usual stalactitical formation, and the somewhat undulating mamillated appearance common to Calcedony, Resides the blunt, heavy, and inosculating varieties.

The lower figures show what is commonly called Bony Calcedony, and have some of the usual appearances accompanied by the more unusual ones of slender thready plates, forming the foraminous appearances which discover to us something more than what is merely stalactitical; and peculiar to the substance itself; probably depending on the nature of the solution, like most Flints and flinty substances; but it never crystallizes as they do, having that appearance only because it has been cast into the places where crystals have been.

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