Prof.  Edward Turner, of the University of London, undertook an analysis of tabasheer, the specimens being supplied from Brewster’s collection (Edinburgh Journal of Science, vol. viii., 1828, p. 335).  His determinations of the specific gravities of different varieties were as follows: 

Chalky tabasheer. 2.189
Translucent tabasheer. 2.167
Transparent tabasheer. 2.160

All the varieties lose air and hygroscopic water at 100 deg.  C., and a larger quantity of water and organic matter (indicated by faint smoke and an empyreumatic odor) at a red heat.  The results obtained were as follows: 

Loss at 100 deg.  C.   Loss at red heat. 
Chalky tabasheer.      0.838 per cent.   1.277 per cent. 
Translucent tabasheer. 1.620  "   "      3.840  "   "
Transparent tabasheer. 2.411  "   "      4.518  "   "

Dr. Turner found the ignited Indian tabasheer to consist almost entirely of pure silica with a minute quantity of lime and vegetable matter.  He failed to find any trace of alkalies in it.

In 1855, Guibourt (Journ. de Pharm. [3], xxvii., 81, 161, 252; Phil.  Mag, [4], x., 229) analyzed a specimen of tabasheer having a specific gravity of 2.148.  It gave the following result: 

Silica. = 96.94
Potash and lime. = 0.13
Water. = 2.93
Organic matter. = trace

Guibourt criticised some of the conclusions arrived at by Brewster, and sought to explain the source of the silica by studying the composition of different parts of the bamboo.  While the ashes of the wood contained 0.0612 of the whole weight of the wood, the pith was found to contain 0.448 per cent., the inner wood much less, and the greatest proportion occurred in the external wood.  On these determinations Guibourt founded a theory of the mode of formation of tabasheer based on the suggestion that at certain periods of its growth the bamboo needed less silica than at other times, and that when not needed, the silica was carried inward and deposited in the interior.

In the year 1857, D.W.  Host van Tonningen, of Buitenzorg, undertook an investigation of the tabasheer of Java, which is known to the natives of that island under the name of “singkara” (Naturkundig Tijdschrift voor Nederlandsch Indie, vol. xiii., 1857, p. 391).  The specimens examined were obtained from the Bambusa apus, growing in the Residency of Bantam.  It is described as resembling in appearance the Indian tabasheers.  Its analysis gave the following result: 

Silica. = 86.387
Iron oxide. = 0.424
Lime. = 0.244
Potash. = 4.806
Organic matter. = 0.507
Water. = 7.632
                   ------
Total. 100.000