PRODUCTION OF STRUCTURAL MATERIALS. 



The production of lime and limestone for the seventeen years totaled 

 $6,262,478, beginning with $368,750 and concluding with $592,268. 



The record of onyx and travertine reads in values, beginning with $900 

 in 1887 and ending with $24,000 in 1896. The biggest output in the ten 

 years was $27,000 in 1893. The total production for the ten years was 

 $91,400. 



More than a million thousands of bricks are recorded for the eleven 

 years beginning 1893. Only in the firebrick and pressed brick trade have 

 the California makers been met with interstate or foreign competition. The 

 brickmakers are, however, gradually reducing that competition, as available 

 clays for firebricks and the finer quality of pressed bricks are being pros- 

 pected and developed. 



The continued increase in the production of petroleum is a part of the 

 mineral history of the State. The record of rapid and steady increase dates 

 from 1889, when the output was valued at only $368,048. The increase 

 continued until in 1894 it reached $1,064,521, and $7,313,271 in 1903. 



The forty-six mineral substances other than gold, silver, copper, quick- 

 silver and petroleum, make the following aggregate annual showing for five 

 years ended 1903, indicating an average annual increase of more than one 

 and one-half million dollars: 1899, $3,392,664; 1900, $5,165,290; 1901, 

 $6,378,723; 1902, $8,333,685; 1903, $9,590,110. 



In 1899 four new industries were developed, adding $20,500 to the 

 output of that year. These were fullersearth ($12,400), lithia mica 

 ($4600), glass sand ($2000), quartz sand ($1500). 



Chrome ($1400) and quartz crystals ($18,000) were added to the 

 productions of 1900, but in that year no production of platinum was re- 

 corded — the only year in seventeen that this mineral failed. 



Graphite and soapstone were the added new productions for the year 

 1 901 , the former valued at $4480, the latter only $1 1 9. 



Antimony, asbestus, quartz crystals and quartz sand failed of recorded 

 production in 1902, and only three new substances were added — chryso- 

 prase ($500), infusorial earth ($2532), mica ($2500). Infusorial earth 

 was not, strictly saying, a new product, but its production had been irregular, 

 and only five tons were recorded between 1894 and 1902. 



In 1903 no new products were recorded, but the production of quartz 

 crystals was resumed to the value of $1968. 



* * * * * 

 ONYX MARBLE A HANDSOME FINISHING MATERIAL 



Onyx marble, or Aragonite (carbonate of calcium), is found in a great 

 many parts of California. This material in its beauty compares favorably 

 with the agate of Lake Superior. Some specimens of onyx marble when 

 polished show a deep blood red like the heart of a rose, others present the 

 appearance of a cloud bank, and there are still others that look like the 

 clouds in the East when touched by rays of the setting sun. Some speci- 

 mens of aragonite are of a chocolate color. In fact, the difference of the ap- 

 pearances of aragonite shows it to be a most versatile substance. Some 

 exceptionally handsome specimens can be seen at the Museum of the 

 State Mining Bureau, Ferry Building. Aragonite is chiefly used for surfac- 

 ing for tables, etc. 



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