Common Name: Darina
Scientific Name: Hymenolobium spp.
Wood Description: Darina, from Hymenolobium spp., has a heartwood that is reddish-brown, sometimes with colored streaks. Freshly sawn surfaces can have a lighter olive hue, with the color darkening to a deeper reddish-brown with age. When fresh, the heartwood is light orange-tan to orange-brown, turning to pale brown on exposure. The sapwood is slightly paler and not always clearly demarcated from the heartwood, or it can be white or grayish with a rather gradual transition. The wood has a uniform, medium-coarse texture, or rather coarse and uneven. The grain is usually interlocked, or straight to interlocked. It has a moderate natural luster, or rather low luster. Alternating zones of dark and light tissue can give a figure of the Partridge wood type. The tree can be medium-sized to very large, sometimes 150 feet in height with diameters up to 10 feet.
Physical Properties: Darina is a dense wood. Its basic specific gravity (oven-dry weight/green volume) is 0.60. The air-dry density is 47 pcf (approximately 753 kg/m³). Other reported densities for Hymenolobium petraeum are 640 kg/m³. The Janka side hardness is 1,720 lb for both dry and green material. The Forest Products Laboratory toughness averages 203 in.-lb. Shrinkage from green to oven-dry is radial 4.4% and tangential 7.1%, with volumetric shrinkage of 10.2%. The anisotropy coefficient of Hymenolobium heterocarpum was less than 1.5.
Mechanical Properties: Darina exhibits good mechanical strength. Its bending strength (Modulus of Rupture, MOR) is 17,610 psi at 12% MC. The modulus of elasticity (MOE) is 2,050 (1000 psi) at 12% MC. Crushing strength is 8,990 psi at 12% MC. The compressive strength parallel to the grain for Angelim-pedra (a common name for some Hymenolobium species) showed significant differences between harvesting regions, influencing its strength class.
Uses: Darina is commonly used in industrial applications, exterior projects, and interior projects such as decking, flooring, and kitchen cabinetry. Its strength and rot resistance make it suitable for heavy construction (exterior applications), boatbuilding, and docks. It is also used for turnery and furniture. It is economically competitive compared to other industrial hardwoods.