192 
EARTHS. AGGREGATE. 61. Porphyrius, 
picem. 
schistQsus, 
nttbus. 
H. With a bafe of pitch. 
CompofecI of pitch, fcldfpar, and quartz- 
Hoffmanu tierg. Journ. 1788. 2. /, 491. 
Picchftone Porphyry. Thomhn. if. p Kir’wan. 
Found r:c.ir Mifena in Saxony, forming entire mountains alter* 
nating with mountains of porphyry and clay, in horizontal 
flraca : colour black, green, brown, or red. 
1 . With a bafe of chert or hornflone, 
Confiftiiig of hornftone and feldfpar, of a llaty texture. 
Hornfchiefer. Charpent , geogr . chuf. p. 21. 24, 25. 28. 
Porphyrfchiefer. PP'erner clafjif. p. r i. feS. 1 1 . 
Honiporphyr. No/e nrogr, i.p. 7. 
Horn porphyry. Kirnuan mineral, t. p. 352-. 
Found common in Bohemia, Lujace, and in the bifhopric of 
rarely containing ores of metal ; colour generally grey, 
rarely black, and often marked with arborefcent ramifications: 
in Italy it approaches to a faafalt, and melts in the fire to a 
yellovvilh glafs, but not fo cafily as bafalt : the chert and 
feldfpar are mixed in various proportions to which is fome* 
times added hornblend, rarely mica, garnets or fpar, very 
rarely veins of marble. 
Confifting of hornflone and feldfpar, of a fplintery tex- 
ture. 
Karsten Lejke mineral. 2. p. z;. 
Hornftohe porphyry. Thorn/, chem. 4. p. 133. Kirnvan 1. 35 *' 
1. Of a texture approaching to conchoidal. 
Horntteinporphyr. Nofe orogr. l. p.\6, 
2. The feldipar very intimately and finely intermixed. 
Hornquartz porphyr. No/e orogr, i . p. 16. 
Hornartiger Trapp. Lalias Beob.Harz. p.17. il z, &c. 
3. With particles of jafper added to the chert and feldfpar. 
Hornartiger Porphyr. No/e orogr. 1. p. 16. 
4. With quartz added to the chert and feldfpar. 
KarHen Lejke mineral. 2. p. 27. 
5. With hornblend added to the chert and feldfpar. 
Karfen Lejke mineral. 2. p. 27. 
Found in variou? proportions of conftituent parts and colours, ih 
the mountains of lower Italy, Hungary, Bohemia, ■ Lu/aeet 
Saxony, Carintbia, the boundaries of the lower Rhine and 
Denmark, frequently exhibiting particles of hornblend, mic* 
and fitorl. 
