COR
COR
( 354 )
Its colour is greyifh or gfeeniffi-white, oryellowifh-green, or fapphire blue, or purplifh-red, or reddifh-brown. It occurs maffive, difle-minated, and cryftallized in the fame figures asTelefia. The cryftals are middle-fized and large.Externally they are for the molt part dull andrough, internally they are tranflucent, femi-tranfparent, and fometimes, though very rarely,tranfparent. Their furface is often covered byftrongly adhering fpangles of mica and grains ofmagnetic iron ore, which laft is fometimesfound difperfed through the interior of thecryftals. Its internal luftre is fhining or gliften-ing, between vitreous and refinous. The termi-nal faces of fome of the cryftals are chatoyant
like Telefia. Its longitudinal fra&ure is ftrait-foliated ; its crols fra&ure is fmall and imper-feftly conchoidal. Its fragments are rhomboidal.Its hardnefs is confiderably fuperior to that ofquartz, and the blue and red varieties are thehardeft. It gives fire with fteel, but not veryeafily. It becomes luminous by friction in thefame manner as Telefia. Its mean fp. gr. is2=3.931, varying on the one hand as far as3.875, and on the other to 3.981.
Adamantine fpar, in its chemical properties,agrees with Telefia. Its component parts ac-cording to Klaproth and Chenevix are as fol-lows:
Adamantine Spar
from the
from Bengal
Carnatic,
Chenevix.
Silex
5-5
5 -
Alumine
89.5
91.
Iron
1.25
l -S
96.25
97-5
Lofs
3-75
2.5
100.
100 .
It occurs in veins in granite and fyenite andOther primitive mountains in India, China , andAva. From its extreme hardnefs, it is in greatrequeft in the Eaft for polifhing fteel, and forcutting and polilhing gems. The Europeanlapidaries however prefer diamond-powder onaccount of the greater rapidity with which itworks,
III. Emery. Schmiergel Werner.
Its colour is intermediate between greyiffi-black, and bluifh-grey. It occurs maffive anddifleminated; when in mafs it is generally in-crufted with magnetic iron ore, pyrites andmica ; the latter fubftance frequently penetratesthe whole mafs, giving it when broken a filveryappearance. It poflefles a gliftening or glim-mering luftre. Its fracture is fine-grained, un-even, palling into even fplintery. It is aboutequal in hardnefs to adamantine fpar, cuttingflint and rock cryftal with great eafe. It isheavy, and not eafily frangible. When moftfree from iron it confifts, according to Tennant,of about
Silex - 3.4
Alumine 92.
Iron - 4.6
from
from
from
from
Malabar
China
Ava
Chenevix. Chenevix.
7 -
5-25
6.5
6.5
86.5
86.5
84.
87.
4
6.5
7-5
4-5
97-5
98.25
98.0
98.0
2.5
*•75
2.
2.0
IOO.
100.
IOO.
IOO.
When highly impregnated with iron it confiftsof about
9 Silex55 Alumine36 Iron
100
Emery is chiefly procured from the Iflands ofthe Archipelago, efpecially from Naxos . It isall'o found at Ochfenkopf in Saxony , in beds oftalc and fteatite, accompanied by calcareous fparand blende.
It is largely ufed for cutting and polilhing bylapidaries, and workers in glafs, fteel, &c.
The fubftance called by Count Bournoncompact corundum, and which accompaniesadamantine fpar, is probably an intermediatevariety between emery and adamantine fpar.Its colour is a deep purpliffi-red, it is opake, hasa compa£t fplintery fradture refembling a coarfejafper It gives fparks when ftruck againft apiece of fteel, and exhibits a fiery red light bycollifion. It is extremely hard. Sp. gr. 3.9. Itgenerally contains difperfed through its fub-ftance particles of magnetic iron ore.
CREAM OF LIME. When well-burnt limeis flacked by water, it falls into a very fine im-
\
10 ®.