In Texas, all property acquired during marriage is presumed to be community. Property acquired before a marriage and during the marriage by gift, devise or descent is characterized as separate property.
Property retains the classification as separate or community regardless of whether it is converted to cash or back again. So for example, if you purchase real property during your marriage with money you inherited, the property will be characterized as separate property. If you sold the property a few years later, the proceeds of the sale would be separate property.
To retain the separate nature of that property, it’s important that you don’t commingle the property with community property. Otherwise it may be difficult to “trace” the property in a way that proves that it is separate property.