Feldspar is the most abundant minerals. There are two types. 1. Orthoclase feldspars contain potassim (KalSi3O8) and usually range from white to pink. 2. Plagioclase feldspars contain sodium (KalSi3O8), calcium (CaAl2Si2O8) or both, and range from white to gray to black,. Feldspars have moderate hardness.

Geologist define rock as aggregates or mass composed of one or more commonly, several of minerals. There are few exceptions to this rule: not all rocks are composed of minerals-for example, coal. Engineers (or contractor) define rock to be hard, durable material that can't be excavated without blasting. The definition is based on strength and durability.

The earth is divided into three main layers: Inner core, outer core, mantle and crust. The core is composed mostly of iron (Fe) and is so hot that the outer core is molten, with about 10% sulphur (S). The inner core is under such extreme pressure that it remains solid.

Defines how the activities are grouped together in P3 working area. Click "Format" menu then select "Organize". Press the "+" sign just below the label "Group By" and select the criteria from the drop down list which you want to use for grouping.

To define a calendar in Primavera P3, click Data in menu and select "Calendars" from the drop down menu. Click holidays to add new holidays.