Slate Information and importance

Slate originates from sedimentary rock far beneath the surface of the earth. Slate is an organic stone with a high content of carbon, calcite and fine grained mica (quartz). Because it is organic , it moves and shifts with changes in temperature and humidity, and as it emits moisture. Being similar to wood in this respect, it forms the perfect adjunct to wood in the construction of a billiard table. These characteristics of slate provide the elasticity which is vital to the proper installation and playability of a billiard table.

Although slate in one form or another as abundant throughout the world, most of it is unsuitable for billiards. For use in billiards the slate must be fine grained, elastic, and have a low propensity to absorb moisture. Slate possessing the precise mineral properties required for billiards is rare. Since most slate is laced with deposits of other minerals, finding large blocks of sufficient purity to make a billiards playing surface is rarer yet. If the slate lacks the necessary homogeneity it is impossible to hone it to the exacting tolerances (1/1000" or less) required for a smooth and true playing surface. At the present time deposits of billiard quality slate and the equipment to hone it properly are largely confined to two countries, Italy and Brazil. Although Italy was for many years the traditional source of billiard slate, in recent years large deposits of high quality billiard slate have been developed in Brazil while Italian producers have faced rising costs and growing supply problems. Not only has Brazil overtaken Italy as a supplier of billiard slate, but raw Brazilian slate is even being exported to Italy for processing by Italian producers.

China is a third potential source of high quality billiard slate. While the mineral properties of certain Chinese slate deposits appear adequate, it remains to be seen whether producers in China will be able to machine the slate to export standards and establish themselves as reliable suppliers.

Buyers should be aware that in addition to 3/4" slate which is usually identified as such, some manufacturers have shaved costs by supplying 7/8" slate standard with their tables. Dealers do not all ways reveal the difference and it is common for 7/8" slate to be passed off as 1" to undiscerning buyers. Thicker slate adds 50 to 150 lbs. to the weight of a table making it considerably more stable. Bump into a 3/4" slate table and the balls will probably move! For that solid feel and quiet, true roll of the balls, 1" slate is a must.

123DiscountSports factory direct tables have 3/4" hardwood framing attached to all of its slate at considerable additional cost. By adding a strip of framing down the middle of the slate which rests on the center beam, exceptional stability achieved, eliminating any possibility of the slate bending out of shape. Hardwood framing, which is required by the Billiard Congress of America for tournament play, allows more precise leveling of the table, and insures that the table will retain its level. Most manufacturers use particleboard or no framing at all. Though less essential in the near term for home use, hardwood is essential in commercial applications where the tables have to be recovered every 8 to 12 months and particleboard will deteriorate with frequent re-stapling of bed cloth. When the slate is unframed the cloth the cloth must be glued to the slate instead of stapled to the framing. Most installers will do a better job stretching the bed cloth taut when they can staple it to the framing.

For more information on slate, such as the serious disadvantages of one piece slate, consult our Consumer Guide

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