S.W. McCallie, State Geologist
Bulletin No. 29
Part III. Talc and Soapstone Deposits of Georgia (p 190)
Varieties of Talc
[ Massive Talc /p 193]
Soapstone is properly applied to an impure form of steatite which contains varying amounts of chlorite, tremolite, pyroxene, magnetite, pyrite, quartz, and carbonates of calcium and magnesium. Its impurity is due to the fact that it is usually derived from the alteration of a basic, igneous rock, often pyroxenite. In common parlance this is the most widely used term, and is applied to any soft rock which can be cut readily. In Georgia it is used extensively to designate rocks in which chlorite predominates over talc; in this report such rock will be designated chloritic soapstones. The latter are commonly derived from the hornblende gneisses and schists. The composition of soapstone necessarily has a wide range of variation.
The ease with which steatite or soapstone may be cut, together with its power of resisting heat, has lead to its use in making vessels for household purposes, whence it is called potstone or lapadis ollaris by older writers.
Origin of Soapstone Deposits
In general, the hornblendic rocks, the gabbros, hornblende gneisses and hornblende schists, give rise to chloritic soapstones, which are of wide distribution in this State. The soapstone thus developed is commonly schistose and might be more properly called a chloritic schist; in some instances, when derived from massive rocks, the soapstone is more or less massive. In almost all cases the rock is sufficiently strong in all directions to be used locally for lining fireplaces, building chimneys, furnaces, etc.
While peridotites may alter directly to talc, this alteration is not so common as that of pyroxenites to talc. Enstatitites, in particular, alter readily to talcose rocks with magnetite as the most abundant impurity. Both the peridotites and pyroxenites alter to amphibolites, which in turn may alter to talcose rocks. This alteration appears to be the most common one which these rocks suffer. Along the contact of the pyroxenite and periodotite dikes with the enclosing gneisses and schists, there is usually developed a layer of talc schist which is quite pure, while the central portion of the mass may be more massive soapstone.
In brief, it may be stated that the peridotites and pyroxenites, the aluminum-poor rocks, alter to talc, while the gabbros, diorite and hornblende schists and gneisses, rocks richer in aluminum, alter dominantly to chlorite.
[ Mining and Milling /p 217 ]
The soapstone deposits of Georgia have been worked for local consumption at numerous places over the Chrystalline Area of this State; but at all of them only comparatively insignificant openings have been made. Practically all these openings have been made into
chloritic soapstone, which has a well developed cleavage and may thus be called a chloritic schist. Taking advantage of this natural cleavage, large slabs are quarried and later sawed into the desired shape with a cross-cut saw. Such are the methods employed in Georgia.
It seems advisable to include here a brief description of the methods employed at the large soapstone quarries of this country. In general, a rectangular quarry is opened up in exactly the same way as a marble quarry. The surface of the quarry is leveled off, benches made, and the rock taken out in large rectangular blocks with the aid of channeling machines, gadders and wedges in the same way as in marble quarrying. These blocks are hoisted by cranes and placed on cars to be taken to the finishing sheds. There is much waste material, estimated from 80 to 90 per cent., due chiefly to the presence of fissures and veins, the weathering of pyrite and magnetite which discolor the rock, and in some cases to the hardness of the material.
The large blocks from the quarries are sawed by gang saws into slabs, as in the marble industry. The slabs are roughly marked off into various shapes according to the use to which the material is to be put, and then sawed on tables with circular saws. These smaller slabs are then smoothed on a revolving disc of cast iron with the aid of water and steel powder. These roughly shaped slabs are finally cut accurately to the correct shape, grooved on emery discs, bored and finished by hand to form the desired articles.
The entire production of soapstone in Georgia has been for the purpose of satisfying the local demand for material for fire places, hearths, chimneys, etc. Since the man producing the material was generally the consumer also, no statistics are available. This industry was much more important years ago than today; the introduction of cement and the location of large granite and marble quarries within the State have largely put an end to it. Thus marble and granite tombstones have replaced the former soapstone ones because of their superior quality and only slightly greater cost; and cement and bricks are used in buildings where soapstone was formerly employed.
[ Uses /p 223 ]
Georgia soapstone has been used locally for a number of purposes, such as tombstones, fire places, chimneys, door steps, foundations, for walling cellars and wells, for lining furnaces, etc. Except in the lining of furnaces, such as are used in connection with cotton gins, the local demand is very small.
The qualities which render soapstone useful are its softness and consequent ease with which it can be worked, its stability as regards heats and acids, and its poor conductivity of heat and electricity. These properties have lead to its extensive use for slabs for table tops and acid tanks in chemical, biological, and other laboratories, as well as for switchboards, panels, and flooring in electric stations. It is also used extensively in the manufacture of laundry tubs, griddles, stove linings, foot warmers, fireless cookers, and many other articles.
Description of Talc and Soapstone Deposits
Soapstone Deposits of Georgia
The chloritic variety of soapstone has a greater distribution in this State that the talcose variety, a result due to the wider distribution of the hornblendic rocks from which it is formed; and, while it has not been examined in every county in the Crystalline Area of the [p 267] State, it would be quite safe to say that its occurrence is distributed to that extent. The largest areas examined are located east of Elberton in Elbert County, near Toccoa in Stephens County, and near Dahlonega in Lumpkin County. In the latter area, the soapstone is purer and of better quality than at the other two localities; however, taking everything into consideration, it seems doubtful whether either of these localities will ever be of value except to satisfy local demand.
Massive soapstone of a grade suitable for sawing into blocks for various purposes, is present in Georgia; but there are so many circumstances to be considered, such as the suitability of the location for a quarry, transportation facilities, the nature of the rock as regards veins, joints, etc., and the extent of the deposit and the likelihood of the rock becoming too hard for use, that it is difficult to [p 268] offer even a casual opinion upon the value of an individual deposit. The most promising one, however, composed largely of talc and anthophyllite, is found north of Dallas on the S. M. Harris and adjoing properties. There are a number of other localities which are worthy of consideration and which are described briefly in this report.
Besides the soapstone deposits described in the following pages of this report, numerous others have been described under the heading of asbestos deposits, the most important of which are as follows: The Wykle and Martin properties in Habersham County, and the L. G. Hardman property in Jackson County.
A. M. Allison Property
Five miles northwest of Cleveland, and 2 miles from Asbestos Station on the Gainesville and Northwestern Railroad, there is a deposit of soapstone which has been exploited to a limited extent for local use. It is situated on the property of A. M. Allison. An outcrop projects above the surface some feet, exposing a mass of chloritic soapstone 12 feet or more in width and 100 feet in length. It is a fair grade of soapstone, and very similar to that on the Elisha Castleberry lot, 1 1/2 miles to the southwest. At this latter locality only about 5 feet of chlorite schist or soapstone is exposed, although it has been quarried here to a larger extent that further north.
H. H. Dean Property
On the property controlled by H. H. Dean, of Gainesville, there is a large amount of chloritic soapstone exactly similar to that described on the A. M. Allison property, ond [and] probably constituting the [p 270] northern part of the same belt. This deposit is located one mile south of Hellen [Helen] and 5 miles west of Nacoochee. The soapstone forms a body at least 40 feet thick and strikes N. 40° E., and dips about vertical. It is exposed near the crest of a small ridge, where it has been quarried for local use, such as in the construction of chimneys, etc. The rock shows a well developed cleavage, and blocks of almost any desired size can be quarried.
Similar deposits are to be found in the same section on the properties of Joe Fain, Charlie Williams and L. G. Hardman.
Robert McMillan Property
A small amount of soapstone for local use has been quarried on the property of Robert McMillan, 4 miles nortwest [northwest] of Cornelia. A small opening about 6 feet wide shows a chloritic schist with a strike N. 20° E. and dip 30° E. The nature of the material, and its association with hornblende gneiss, naturally leads to the belief that it was derived from the latter.
The rock from this locality was used locally for tombstones until marble became so cheap that it destroyed the market for the soapstone.
Similar material has been found in the town of Demorest near the residence of C. W. Stambaugh, at the north end of the lake.
Stephens County is underlain largely by Carolina and Roan gneiss, with granite in subordinate quantities. The Roan gneiss is well distributed in narrow bands over the southeastern half of the county, and is relatively most important southwest of Toccoa and near Tugaloo. From 2 to 3 miles southwest of Toccoa the Southern Railway cuts through an area of what appears to be quartzite, although it may be a very siliceious metamorphosed granite. It is seen
Lumpkin County contains a large amount of basic rocks, ranging in composition from hornblende gneiss to peridotite and pryoxenite. They are associated with the Carolina gneiss, with which they are intimately folded. The Carolina gneiss is also quite variable in composition, and consists largely of mica schist, in some places highly garnetiferous, mica gneiss and slaty schists; a large part of it has the appearance of a highly metamorphosed sedimentary rock. Granites of several periods of intrusion are present, are vary in structure from massive to gneissic.
There is, relatively, a large amount of soapstone of the chloritic type present in this county, and it is very similar to that described from south of Dawsonville, 13 miles east of Elberton, and 8 miles east of Toccoa. Some peridotites and pyroxenites, much altered from their original composition, are present in small areas; at but few places do they give any promise of yielding asbestos or soapstone in commercial quantities.
Description of Properties
Four Miles East of Dahlonega
On the east side of the Chestatee River, 4 miles by air line east of Dahlonega, there are a number of exposures of chloritic soapstone, and several small openings where the rocks have been quarried for local use. One of the main exposures is on lot 121, 15th district, and 1st section.
The width of the soapstone dike reaches a maximum of 200 feet, but further north it decreases to 30 feet. The rock is massive in structure where it is not weathered, and is capable of being cut into blocks of almost any size. Chlorite predominates over talc, and appears to form the body of the rock with, at places, small amounts of magnetite and amphibole needles. The material here exposed is [p 274] much better than the average of this type found in Georgia, and could be used for many of the purposes for which a medium grade soapstone is employed.
Soapstone from this locality has been used in Dahlonega in the construction of fire-places, such as at the Mountain Club House, and for tombstones, as at the Yellow Creek Church, near Murrayville.
The largest quantity of soapstone found in Lumpkin County is located on what is known as Soapstone Ridge, 9 miles northeast of Dahlonega and 7 miles west of Cleveland. The soapstone occurs as parallel bands, the widest of which is several hundred feet, which strike a little east of north and can be traced at least one mile. The soapstone is mainly a greenish, schistose, chlorite rock which, in places, usually near the contact with the country rock, becomes somewhat talcose. There is much variation in the soapstone, and it is found to grade to an amphibolite, or, more exceptionally, to a somewhat massive rock which appears to represent an altered diorite. The best soapstone is found in lenticular form, either enclosed in the less altered rock, or along the contacts with the country rock.
When studied microscopically, the rock is found to contain chlorite, little or no talc, amphiboles (actinolite and probably some anthophyllite), carbonates and magnetite. It is evidently derived from the hornblende schist of the Roan series.
The soapstone has been used locally, and small quarries have been opened. The deposit occurs on the properties of W. M. Grindel, A. C. Bowen and others. (See plate XIX, fig. B.)
Soapstone similar to that described above and to that described as occurring 4 miles east of Dahlonega, is found in an intermediate position on the property of J. R. Dowdey, 5 miles northeast of Dahlonega.
These three localities are in a line represented by the strike of the formation, and may, or may not, represent parts of the same body.
Other Localities in Lumpkin County
A dike of amphibolite (or hornblendite) is found one mile southeast of Porter Springs, a locality where corundum is reported to have been found.1 the rock is composed almost entirely of hornblende, which is in places partly converted to chlorite. The intrusion is 60 feet wide and at least 300 feet long.
On the property of C. M. Motes, 3 1/2 miles northwest of Porter Springs, there is a small soapstone dike only a few feet wide which consists largely of chlorite.
One mile further west, on the property of William Gooch, there is another dike 200 feet long and 50 feet wide, which is partly a talcose-chloritic rock. It is associated with mica-cyanite schist and hornblende gneiss.
West of Dahlonega, there are numerous small areas of chloritic soapstone similar to those described above. On Earl Davis' place 3 1/2 miles west of Dahlonega, soapstone is found which is clearly derived from an altered, basic rock, probably a gabbro. (Plate XIX, fig. A.)
Practically the whole of Dawson County is formed of Carolina and Roan gneisses, with some granite intrusions in the southeastern part near the Etowah River. The general types of the Carolina gneiss are mica schist, in part garnetiferous, and biotite gneiss, all of which give some indications of being of sedimentary origin.
Two prominent bands of hornblende gneiss and some associated soapstone cross the southeastern part of the county, one about 2 miles, and the other 3 1/4 miles, southeast of Dawsonville. The soapstone associated with these hornblende rocks is of low grade and has been used locally for chimneys, window sills, for walling wells, and similar purposes. It is green in color, possesses a very pronounced schistosity, and for this type of material is moderately free from grit.
1 King, Francis P., Corundum Deposits of Georgia: Bull. Ga. Geol. Survey, no. 2, 1894, p. 96.
A. Outcrop of soapstone near Dahlonega, Lumpkin County.
B. Small opening into chloritic soapstone on Soapstone Ridge, north of Dahlonega, Lumpkin County, showing schistose structure.